Image search is the silent giant of web searches. Nearly 19% of search queries on Google are image searches, and these numbers will only grow with recent developments in Artificial intelligence (AI) and machine learning (ML). These resources will further enhance the search engine’s ability to understand images rather than just indexing them.

Google has revolutionized image search over the years. It ranks images to help users find content behind the image that’s most relevant to their query. Its revamped interface now includes filters, attributions, and metadata that best describe how the image fits in the larger context and user query.

What’s more, Google has introduced structured data, text snippets, image previews on mobile, and ‘swipe to visit’ to improve the user’s visual search experience.

Thus, it goes without saying that if you’re not optimizing the images in your content, you’re likely wasting a valuable SEO asset—especially if you have an ecommerce store!

Just look at how ranking an image for an important keyword can get you valuable traffic:

Carousel Results by Google
Carousel Results by Google

What Is Image SEO

Image SEO is the process of optimizing images on a web page to attract both visitors and search engine crawlers alike. The goal is to boost the images’ search rankings and visibility. Image optimization offers various advantages, including faster page load times, improved user experience, and additional ranking opportunities.

Image SEO Best Practices

Choose The Right Image Format

Each image format has a different structure and, thus, different file sizes, which ultimately contributes to overall page size and load time.

There isn’t a one-size-fits-all approach when it comes to choosing the right format; the image format you choose depends on the type and the intended use of the image.

Here’s what we recommend:

  • JPEG is your best bet when it comes to illustrations or larger photos. It offers good quality with a relatively small size.
  • PNG allows you to preserve the background transparency and produce better quality images.
  • If page speed is an issue and you need images with smaller file sizes, choose WebP instead of PNG or JPEG.
  • Icons and logos are best displayed in SVG format. You can resize SVG images with the help of JavaScript or CSS, without compromising on quality.

Compress Images

According to the HTTP Archive, images make up for 21% of a website’s weight.

The longer a visitor waits for your web page to load, the more visitors you lose, and your bounce rate increases. Therefore, we recommend compressing images before uploading them to your site to ensure that they’re served in the smallest possible file size.

You can use TinyPNG and WP Smush to reduce the image file size without downgrading the quality.

Once you’ve optimized your images, you can test your site speed with tools like Google PageSpeed Insights or Pingdom.

Customize Image File Name

Descriptive keyword-rich texts always win with SEO even if they’re just file names!

Replace those standard image file names like “IMG_34242” with something meaningful like “iced-coffee-recipe” or “summer-jacket.” Image file names signal search engine crawlers about the subject matter of your image, improving their chances of ranking when users type similar terms in the search bar.

Optimize Alt Text, Title Text And Captions

Alt text (alternative text) is a description of the image that the browser displays if there’s a problem in rendering the image. According to Google, alt text allows screen readers to read the image text and help people with visual impairments understand what the image is about.

Alt text is a descriptive blurb about your image that is meaningful yet concise. You can remove conjunctions (like a, an) in these descriptions.

Most importantly, make sure your alt text includes the SEO keyphrase for that page.

Some browsers show the ‘title’ text of the image as a tooltip, which gives you a good opportunity to include additional information about the picture.


Image captions accompany the image on a web page. Remember, any element that enhances the ability to scan content, such as bold headings, highlighted text, captions, graphics, and table of contents, improves the page’s readability. Consequently, these elements also improve user experience.

Having said that, be careful of over-optimization. Not every image requires a caption; only add captions where you think it would make sense for the reader.

Responsive Images

Responsiveness is a no-brainer when it comes to SEO ever since Google rolled out mobile-first indexing. Now websites are indexed based on their mobile versions rather than their desktop versions.

Responsiveness ensures that the size of the images on your webpage automatically scale and adjust to the size of the device used, whether the visitor is using a mobile or desktop. A responsive site is the first step in delivering good user experiences.

To make images responsive, add the srcset attribute in the image source code. This piece of HTML code signals the browser to load different versions of an image based on the screen resolutions. However, you won’t have to add this attribute if you’re using a CMS like WordPress.

Add Images To Sitemaps

XML sitemaps help search engines discover all the relevant content on your site; this applies to images too.

Whether you decide to create a new sitemap for images or add images to your current sitemap, Google recommends that images in XML sitemaps increase the likelihood of search engines discovering, crawling, and ranking your images.

If you don’t use WordPress, the best way to go about adding images to sitemaps is to use Google’s Webmaster Tools or any other XML sitemap generator.

Add Image-Structured Data

Adding structured data or schema markup is another way of adding details to your image at the backend to help search engines understand your images.

Did you know that if you add structured data, Google might add a badge to your image? These badges appear on thumbnails in mobile search. Currently, Google only supports four markup types: recipes, products, videos, and GIFs, so make sure you add appropriate markups to your content.

Google Images Search Results
Google Images Search Results


Image SEO is complex, and Google has tons of guidelines on image optimization that you can go through. High-quality and well-optimized images not only improve the readability of your content but also improve your odds of ranking in search results.

With a comprehensive website SEO audit tool like Rank Genie, you can fix and optimize all the on-page elements on your site, such as the quality of your internal and external links, your sitemaps, metadata and descriptions, your image SEO, and more. Start your 7-day free trial for Rank Genie today!