Ultimate Guide to Image SEO

12 Proven Image SEO Optimization Secrets To Boost Your Traffic with Images

Image SEO is one of the important parts of on-site SEO that is often overlooked by website owners.

This is why, it is common to find websites which have images with nondescript file names, wrong file format, huge file size and displaying at far smaller dimensions than the original image,

Correctly optimizing your site’s images for Google will make your website more competitive in the search engines and can drive significant amounts of traffic to your site.

In this ultimate Image SEO guide, we are going to look at all the image optimization practices you can use to optimize your images for better results.

Image seo guide

Let’s get started..

Why Images are so important?

Over the year studies have shown that humans remember 80% of what they see compared to 10% what they hear and 20% of what they read.

In fact, a survey suggests that approximately 65% of the population are visual learners.

MIT also found that the human brain can process visual images in as little as 13 milliseconds.

All these stats give a clear idea that images are powerful and preferred mode of communication compared to texts.

When it comes to the website, high quality and relevant image matters because of their role to capture the attention of the visitor.

Importance of visual graphic

They can convey complex messages in the blink of any eye. Looking at the image of an apartment, the site visitors can quickly get the idea of its amenities and home plan, without the need of reading the lengthy description of the apartment.

Since images play an important role in how a site visitor engage and interact with your content, it also affects your site’s SEO because Google’s algorithm pays attention to behaviour metrics that reflect user experiences (Bounce rate, Dwell time, etc).

Important Information –

What is Image SEO & Why it is important?

Google image search has become increasingly important for the website owners in the past few years.

In February 2018, Google finally removed the “view image” button from its image search results, which led more and more people to visit the actual website to see an image.

With this small change, most websites started to notice an increase in traffic through image search. In fact, some of the websites experienced 47% increase in traffic after the update.

Since Image search has huge potential to bring tons of traffic, Image SEO is all about using different practices that will help Google better understand your site’s images and rank higher in the image search result.

It is also important to understand that image SEO is not just about helping Google to understand what an image is about.

Poor image optimization is one of the big reason of slow website loading time and high bounce rate. So, proper image optimization can have a big impact on how fast your site loads and how much time people spend on your site.

Helpful resource: An ultimate guide to load your website fast!

How to optimize your image for Google

There are several tasks that’ll help Google better understand your site’s images and give a good experience to your site users. Let’s discuss each of them one by one.

01. Always use images that are related to your content

Images are meant to give user better understanding of the information you are trying to convey, and they strengthen the signals to search engine about the relevance and quality of the content.

This is why including related images with your content topic, with similar content in the image helps you rank better in image SERPs.

For example, let’s say you are trying to rank for productivity printable, including different image containing productive planner in A4 size will increase your chance of ranking for the same term in Google.

Here’s a proof – the majority of images ranking for “productivity printable” in image SERP are actually productivity planner rather than any usual stock photos.

Productivity printables

02. Create Unique Images as much as possible

It is very tempting to fill your site with stock imagery since they are easy to find, cheap and sometimes even free.

But in reality stock photos indirectly harm your website, as they do not provide your audience with original content or a good user experience.

Think about how many times you’ve seen a corporate website or a consulting firm use the same photos of a businessman smiling at you.

I am sure you have seen one look like this:

Stock images on google

Not only these photos can feel bogus, but it can be a poor experience for your users to see the same image again and again across multiple sites.

When asked “does using stock photos on your page have negative impact on ranking”, this is what Google’s former Head of Webspam, Matt Cutts had to say:

“Having stock photos on your site currently doesn’t harm search engine ranking. However, that’s a great suggestion for a future signal that we could look at in terms of search quality. Since website using original images might be higher quality, whereas site just repeat the same stock photo over and over again might not be nearly as high quality”

Typeform and Venngage also conducted a survey on visual content marketing and found that although more web publisher uses stock photos in their digital marketing campaigns, but original graphics are more valuable in reaching their end goals.


Bottom line…..

Stock photos might be easier and cheap to get, the original images are always going to perform better for you.

What to use instead of cliché stock photos:

  • Illustrate your facts and stats with canvas or Photoshop

If your web content is full of juicy facts and figure, you can use a graphic designing software to create eye catching illustrations.

All the custom illustration, charts and visual graphics you see on my website are made with Photoshop software.

graphics and illustration
Custom Graphics and Charts made with Photoshop Software
  • Edit the stock photos to match with your brand.
  • Take screenshots and highlight useful area:

If your content is technical in nature or you are sharing a tutorial, you can include screenshots to better illustrate your point.

For example, if you look at my SEMrush content marketing toolkit tutorial, I have added more than 50 screenshots demonstrating how to use the tool.

screenshots graphics
some examples of custom made screenshot use in one of my article
  • Use your own camera or smartphone to take original photos

If you are running a food blog, DIY blog, Interior blog or Fashion blog, you can use your own smartphone camera to take real pictures.

People will find those original pictures more interesting and authentic than cliche stock photos.

Recommended reading – Technical SEO Audit (A guide to optimizing your website for crawling & indexing phase)

03. Choose the Right Image Format

The image format you choose while saving your image have a lot of impact on your site’s performance, apperance and scalability.

Although, there are dozens of image file format available to choose from, but there are three most commonly used file format :- JPEG, PNG and GIF.

JPEG – This is one of the most widely used image formats online and an excellent option for real-life images, like photographs with lots of colours. However, it produces lossy images, that means you’ll lose some minor image details every time you save your photo. But the best thing is you’ll have full flexibility to adjust the quality level for a good balance of quality and file size.

PNG – Portable Network Graphics (PNGs) are ideal for illustrations, infographics, images with lots of text in them, and logos. Images saved in PNG format are usually higher quality than JPEGs, but typically but also has a larger file size too. One big advantage of using PNG is that it supports transparency which makes it go to option for logos and icon.

GIF – GIF stands for graphic interchange format. It is an eight bit file type, which means it supports way less color than JPEG or PNG would. Unlike the two formats I have talked about so far, GIF has far more specific use cases. Most of the people use this format to show animated image.

All the above three formats are used for raster images (pixel-based images), but then for vector images the most popular image format being:

SVG – Scalable Vector Graphics (SVG) is actually a text file that describes shapes, line, curves and colours in a language called “XML”. Unlike raster image formats seen in JPG, PNG and, GIF, an SVG image remains crisp and clear at any resolution or size. And because they are text-based, they usually have smaller file sizes and can be customized with CSS code.

However, due to security reasons, the SVG file format is not supported in WordPress by default, but you can easily enable SVG upload by following this simple guide by BetterStudio.

If you’re still not sure what format is best for your image, this chart might help you:

How to choose image file type

The next gen formats

If you have run a Google Pagespeed test of your website recently, it’s likely that you have got a recommendation that says “Serve images in next-gen formats”

page speed recommendation on next gen format

Next-gen image formats (JPEG 2000, JPEG XR, and WebP) are file formats that have superior compression capabilities and outstanding quality to please the web users.

This means image saved in the next gen format have very low file size and load super fast on website.

In fact, according to Google report, WebP lossless images are 26% smaller in size compared to PNGs and WebP lossy images are 25-34% smaller than JPEG image.

Now the bad news. As of now, not all web browser support these next generation image file type.

So, how do you start taking advantage of the wonders of next-generation formation like WebP, without leaving out the users of browsers that don’t support it yet?

Well, this is where an all-in-one image optimization plugin like Shortpixel comes into use.

Shortpixel plugin webp support

Within a click, the plugin will make sure to show WebP format of your image to users whose browser support this format.

Recommended reading – Best sites for Guest Blogging (List of websites that accepts quality guest pots without any charge)

04. Save your image in the right dimension

Another common issue with images is that the image file dimension is much larger than the actual image dimension that is being used on your website.

For example, the camera of iPhone 12 produces images of 4032 x 3024 pixels, but the maximum width that this image display on your website will be 700 pixels (depending on max-width of your blog content).

The important thing to understand here is that the difference in file size between a photo that is 4032 pixels wide compared with 700 pixels wide will have a huge difference, and using multiple images that are larger than their display size of your website can qucikly contribute to a heavy page file size.

The bottom line…

Use image dimension thats appropriate for your page width. One more thing – it is not necessary that your image size should exactly match your page width, it can be slightly bigger (since very small dimension image can result in blury photo).

What about the mobile phone and tablet devices?

Obviously, the page width of your website appearing on mobile & tablet device will be way smaller than the desktop width.

So, serving an image of desktop width would be unnecessary and slow-down your page.

Luckily after the WordPress 4.4 update, it takes care of the whole process of automatically resizing the image for small screen devices.

If you are not using WordPress CMS, you can implement responsive images using CSS with the help of this guide by W3 school.

How to resize your image?

Many website experts might suggest you to use a plugin or service to automatically resize your image after you upload them in your media library.

However, it doesn’t make any sense to store a 5 MB image on your website even if you resize it afterwards.

So, it’s better you resize them before uploading and prevent them from eating your hosting’s disk space.

Use free software like Paint or a photo editor like Photoshop to resize your image into your preferred dimension.

Resize photo in MS paint
Resize your photo in MS paint within a click

05. Use a compressor to reduce image size

Selecting the right format and resizing into the optimal dimension is one part of the image SEO optimization, But rightly compressing the images without losing the quality is a whole other challenge.

But why image compression is actually important?

See, we all want to show high-quality images on our website, but high quality always translates into very big file size.

And as of now, you understand it very well that a larger image file will take more time to load and slow down the website speed.

This is where ” Image Compression” comes into play…

Image compression is the process of using compression algorithms to reduce the size of an image file without degrading the quality of the image to a greater extent.

Here is an example of original image vs compressed image:

Image compression
Image compression without any changes in image quality using Shortpixel plugin

Ass you can see there is little noticeable difference in quality between the two images. Yet the second image is 69% smaller than the first image (368kb vs 114kb)

How to compress your image file?

The best way to compress your image is by using Photoshop or any other graphic designing software before you upload the image to your site.

This will give you a lot more control over the quality of images on your website.

However, not all website owners are comfortable working with advance software like Photoshop. Because for most of the people, optimizing every single image before uploading can sound like a lot of work.

Luckily, there are several wordpress plugins that can automatically compress and reduce your image file size after you upload them on your site.

The most popular ones are ShortPixel, EWWW, TinyPng, Imagify and Smush.

To find out the best among them, I decided to run a little experiment.

I took two images (one PNG format and one JPEG) and compressed them with all the tool one by one.

Here’s what the final result came out for JPEG:

PluginOriginal SizeSize After compressionReduction percentage
TinyPng230 KB86.8 KB62%
EWWW230 KB 156.4 KB32%
Shortpixel230 KB64.5 KB71.9%
Imagify230 KB146 KB36.5%
Smush230 KB194.2 KB15.5%

Here’s what the final result came out for PNG:

PluginOriginal SizeSize After compressionReduction percentage
TinyPng425 KB295.2%30%
EWWW425 KB 380 KB10.5%
Shortpixel425 KB185 KB56%
Imagify425 KB325.5 KB23.4%
Smush425 KB310 KB27%

From the above data, ShortPixel clearly stands out among all and this is the one which I use on NerdBloggging too.

This plugin gives you the best results by making the maximum difference in image file size (both PNG & JPEG).

Apart from image compression, Shortpixel also has plenty of image optimization features like lazy loading, WebP support, file format conversion and many other.

Start using ShortPixel on your WordPress site

06. Use Descriptive and Distinct metadata

While search engines are getting better at understanding what’s in an image, you should not totally rely on their ability, at least for now.

You should do everything from your side to help them understand your website images.

With properly writing image metadata, you can be sure that Google or other search engine rank your image for the right term in SERPs.

With that being said, here are the most common and important image metadata:

  • image file name
  • alt text
  • image caption
  • title and description

NOTE: Image metadata are not just used for search engines. Even if you have no intention of ranking image in Google search, there are still benefit of writing proper image metadata.

They are useful for helping website vistor understand what the image is all about, without being able to see it.

How to name images for SEO?

The name of your image is the first thing to check before you add them to your website.

According to Google’s own image best practice guide:

The image file name should be descriptive and keyword rich to get the most SEO power.

When you take a photo using your DSLR camera or smartphone (even take screenshots), they are given generic filenames like DC0001IMG.jpg (or something similar) that do not make any sense.

Change it to somethings that descriptive and relevant that helps to give context to what it shows.

how to write image file name for SEO

How to write alt text for image?

Alt-text (alternative text) is an HTML attribute added to the img tag to describe the appearance and function of an image on a page.

It looks something like this in plain HTML code:

<img src="brownies.png" alt="Chocolate Brownies with Strawberries"/>.

Even though search engines are getting better & better at image recognition with the help of AI technology, they’re still not perfect in understanding what an image is about.

The alt tag is one of the most important elements that help search engine crawlers understand the subject matter of the image.

Here is what Google’s John Muller said when asked about the importance of alt tag:

Google's John Muller tweet about importance of alt text

In addition to helping with SEO, image alt tags also help your website visitors.

Some of your website visitors might have image display turned off, their browser can not load image because of slow internet or they’re using a screen reader due to visual impairment.

In all these cases, Image alt text tells them what the image is exactly all about. So, that they don’t have to miss out the information provided by your images.

Tips for Writing SEO-Friendly Alt Text for Your Images

  • Describe the content of the image in as much detail as possible.
  • Use unique alt text for each image on your page.
  • Don’t use dashes in your alt text to differentiate two words, instead use sapce as you normally do.
  • You can use keyword in your alt text, but the keyword should be closely related to your image content.
  • Write alt text with keeping actual readers in mind, not just search engine crawlers.
Image Alt text for seo

Image Title & Description

The title and description of your image don’t have much to do with front-end of your site.

The same way you would name your email lists or landing page to organize them for internal use, title and description of images similarly help you internally organize images in the media library.

Image title in WordPress

However, in case you have attachment page enabled on your site, the title used for the image will also appear as the headline (H1) on the attachment page.

Write caption if needed:

Caption – a short bit of text often found right below an image – may not have a direct impact on your image SEO, but, unlike other metadata, it is actually visible on your web page for the user. For this reason, they can add to the better user experience.

In fact, according to Neil Patel studyCaptions under images are read on average 300% more than the body copy itself.”

Image caption

So using the appropriate caption (when needed) can keep your readers engaged with your content and story.

07. Create an Image Sitemap

A sitemap is a file that lists all pages of your site to tell the search engine about the organization of your site’s content.

It is an important part of SEO because it helps search engine crawlers find all the pages of your site that need to be crawled.

Very similar to page/post sitemap, Google recommends web owners to create a sitemap for their images too.

It will give Google additional details about your images, and provide the URL of your images that might not have otherwise discovered by crawlers.

As for creating your sitemap, you have two option:

Update your image sitemap manually:

If you run a small portfolio kind of site (20-25 pages), it would not take much time to manually create a image sitemap for your site.

Here is an example that Google has provided to understand the basic format of image sitemap:

Image sitemap format by Google

While the sitemap format shown above only using image and location tag, you can also use caption, title, and, license information to provide more information and a better user experience.

However, the one problem you’ll face this method is that you have to manually update your image sitemap every time you add a new image to your website.

This might not be a big problem for someone who adds a new page in a month or two, but for someone who is running a big website and updating daily with new posts, it’ll be a serious problem.

This is where second method comes into play:

Automatically include every image in your sitemap:

If you are a WordPress user, the best way to automatically generate & update your sitemap is to make use of your SEO plugin.

For example, I use Rank Math SEO plugin on my blog. So, I just need to enable “include image” option, which will automatically generate image sitemap for my site.

Rank math image sitemap

08. Leverage Browser Caching

Browser caching is where your image and other file stored in your site visitor’s browser.

Thus, when they re-visit your same page, images are locally sourced from their caches and served to them immediately.

For example, when you visited this page for the first time, your browser had to download all the image used on this page (in the back-end) before displaying on your screen.

Now, if browser caching is not enabled on my site, this download process needs to be repeated every time you visit this page.

However, with browser caching enabled, what happens is that your web browser download & store all the image and other files like HTML, CSS & JavaScript on your computer.

So, when you visit that same page or a similar page again, there’s no need to download all of them. Since they are served directly from your computer, the site will load much faster.

Here’s what Google has to say about browser caching:

HTTPS caching

In fact, Google page speed insight also recommend enabling caching to increase page speed user experience.

Page speed insight recommendation on caching

So, how do you enable browser caching on your website?

Well, for WordPress user, the process is very simple. All you need to do is download and activate WP Rocket plugin on your website. Then the caching functionality will be by default enabled on your site.

Cache plugin

If you are not using WordPress, you can add this code to your .htaccess file manually to enable image caching:

<IfModule mod_expires.c>
ExpiresActive On
# Images
ExpiresByType image/jpg "access 1 year"
ExpiresByType image/jpeg "access 1 year"
ExpiresByType image/gif "access 1 year"
ExpiresByType image/png "access 1 year"

Additional resources:

09. Host Images on a CDN

In most cases, your website will be hosted on one server at a particular location.

Now, imagine a scenario, where your site is hosted in Los Angeles (US) and someone is visiting your site from India (Asia).

In this case, your site’s assets such as Images need to travel further to India, slowing down to load your page (because of long-distance travel).

This is where a CDN (content delivery network) comes into use.

A CDN caches your site’s images & other assets across their multiple servers at different locations across the world.

And when an internet user requests any of your pages, they are served from location (data centre) closest to them.

Without CDN, everything served from one main data center
CDN speed
With CDN, assets are delivered from data center closest to the user’s location

Some of the most popular content delivery network (CDN) service provider includes Cloudflare, Amazon CloudFront, Fastly, and Stack Path.

I personally use StackPath for all of my blogs, since their customer support service and the user interface is top-notch.

10. Implement Lazy Loading

Lazy Loading is a method of deferring (delaying) the loading of images (& other resources) that is not needed on the page immediately.

In simple terms, with the use of lazy loading, images are not loaded immediately when the page load, it is loaded only when the user scrolls and the image actually become visible. Which eventually speed up the performance of your site, especially on mobile.

This means if a site visitor’s do not scroll all the way down, images placed at the bottom won’t even be loaded.

Here is what Google has to say about lazy loading:

why use Lazy loading

Although, there has been a lot of debate in the past as to whether lazy loading technique is good or bad for SEO.

In fact, Google was also giving mixed message about lazy loading in the past.

Google on Lazy loading

However, Google gave a clear indication about lazy loading through their PageSpeed insight tool in 2018.

Pagespeed insight reccomend lazy loading

Google has also created an extensive guide on how to implement lazy loading in the right way so that they can see the lazy-loaded content easily.

If you are a WordPress user, there are a couple of useful plugins available for lazy loading like A3 Lazy Load plugin.

However, since I use WP Rocket caching plugin on my blog, it has an inbuilt option to enable lazy loading for image & video. So, I don’t have to download any additional plugin for this purpose.

Lazy load wp rocket

Recommended reading – On page SEO techniques for higher ranking in search engine.

11. Disable Attachment Pages in WordPress

When you upload a file such as an image on your website, WordPress by default creates a separate page for each media attachment.

This page contains nothing except a full-size image, and has its own automatically generated URL.

This functionality might be great for the photographers or stock photos website, but not for the rest of us.

From the SEO point of view, it can have a negative impact on your site. Since, Google consider pages with little to no text as low quality or in SEO terms – ‘thin content’.

This is why it is recommended to disable the attachment page on your WordPress site.

If you are using an SEO plugin like Yoast SEO or Rank Math, you get an in-built option to disable and redirect your attachment page.

Rank Math user:

  • Open your Rank Math dashboard.
  • Go to general settings.
  • Click on “link” tab.
  • Toggle the ‘Redirect Attachment” option.
Redirect Attachment Rank Math

Yoast SEO user:

  • From your WordPress dashboard’s sidebar, click on “SEO”.
  • Click on “search appearance”.
  • Go to the “Media” tab.
  • Toggle the ‘Redirect attachment URLs to the attachment itself?’ option.
Redirect attachment Yoast SEO

If you are not using any of the SEO plugins, you can also install a plugin called Attachment Pages Redirect.

This plugin will redirect people visiting your attachment page to its parent post where the image is displayed.

If you don’t want to install any plugin, you can also manually create a new file called image.php in your child theme and paste the following code.

global $post;
if ( $post && $post->post_parent ) {
	wp_redirect( esc_url( get_permalink( $post->post_parent ) ), 301 );
} else {
	wp_redirect( esc_url( home_url( '/' ) ), 301 );

This code will make sure to redirect the attachment URL to the original post where the image was used, or if the image was directly uploaded in the media library it will redirect to your site’s homepage.

12. Add Structured Data (Image Schema)

Structured data, also referred to as schema markup helps you add back-end details to help search engines understand the content of a page better.

It also increases the chances that your content can show up as a rich result on SERPs.

Here is an example of a rich result in SERP:

Schema markup in SERP

But did you know that structured data (or schema markup) may also be relevant for Image SEO?

Here is what Google has to say about this:

Image structured data

For example, here is the result I get, when I searched for “how to make pasta”.

Rich result in Google SERPs

If you notice, every result appearing for this term is having a complementary image. That’s because Google knew to associate these recipe pages with images based on the structured data provide by site owners.

It’s not just about the recipe, currently, Google Images supports structured data for products, recipes, videos, and GIFs.

If you use the right schema, Google will also show relevant badges on the thumbnails in image SERPs.

Image schema showing badge in SERP

How to add structured data to your page?

If you are a WordPress CMS user, adding any type of schema markup to your page is pretty simple. All you need to do is install a plugin called Schema Pro on your website.

Schema pro

Note: It is important to note that there is no separate schema markup for Image, rather an added benefit to those using product schema, recipe, or video markup.

Final thought on Image SEO & Optimization

Images are one of the most powerful weapons of your website.

When used correctly, they can have a significant contribution in making your content more accessible, attractive, and engaging to users or, when used poorly, they can ruin all your hard work.

That’s why it is important to properly optimize your image to improve the likability of your content by both humans and search engines.

Image Optimization Key Takeaways:

Here is a summary of all the image optimization best practices shared above:

  • Don’t use images just for the sake of using image. Use image that has greater puropse and bring added value to your content.
  • Try to create as many unique images as possible rather than using stock photos.
  • Choose the correct format for your image. (JPEG for normal photos, PNG for screenshots & illustrations, GIF for animations)
  • Use next-generation file format like WebP for the browser that already supports them (Firefox, chrome & opera).
  • Save your image in the dimension that matches your website’s layout. Although, remember that WordPress now supports responsive image to serve different versions scaled for different devices.
  • Compress your image with the help of a plugin like Short Pixel to reduce the file size.
  • Don’t upload an image with their default file name. Give it a descriptive name that matches its content.
  • Use Alt-text that accurately describes your image (important).
  • Add captions (if needed) for easier scanning of the content.
  • Create a separate sitemap for image for better crawlability.
  • Leverage Browser caching and use a CDN to serve your image faster.
  • Disable attachment page in WordPress.
  • Use structured data (if appropriate) to give more context of your content.
  • Implement lazy loading, if you have many mages on a page.

These were some best practices when it comes down to how to optimize image for web and SEO.

Now I want to turn it over to you:

Let me know which tips from today’s post are you going to try first?

Or maybe anything about image optimization that i missed here..

Either way, let me know in the comments below.

Oh, make sure to check my latest WordPress SEO checklist to ensure you are utilizing WordPress to its best.


Hi, I am Shivam Choudhary founder of Nerdblogging.com – A blog that helps online entrepreneurs start, grow, and scale their blog. Whether you are looking for the right advice to get your blog off the ground or proven strategies to accelerate your blog’s growth, I am here to help you get further. 

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