Image SEO checklist
Click to hear an audio recording of this post

The internet generation, search engines, and social media platforms — everyone loves visual content. And so, no modern website is complete without high-quality images.

But simply infusing high-quality images into your website content isn’t enough. Your competitors are doing that, too.

To realize the true returns on your image-inary investments and drive greater organic visibility, traffic, and user engagement than your competitors, you must step up your image SEO game.

In this infographic-blended-blog-post, you’ll learn some quick and actionable pointers on how to fully optimise your website images for SEO, from image ideation to post-upload. Check off this definitive list and you’re all set!

If you need help with image SEO you can always reach out to our SEO company.

Why optimise your images?

As just touched upon, image SEO is all about optimising your website’s images so they rank higher on Google and perform better in terms of user engagement.

But is it worth the effort? Look at the numbers below and decide:

So the short answer is: yes, it’s worth investing the added time and effort that goes into optimising your website images. Let’s see how you can do it right.

The ultimate image optimisation checklist for SEO

For the most part, image optimisation for SEO is an extensive yet straightforward process. Here’s a definitive image optimization checklist you can check off for each image you ideate, create, and upload on your website.

Image ideation checklist

Using images is always a good idea, but having images that are irrelevant or have no real context would do your page little good. So, when ideating images for a page:

  • Think of images that are relevant to and reinforce your content:
    • A short infographic that summarizes your article or research
    • A screenshot to support a brand example
    • Product images from multiple angles
  • Steer clear of obvious stock images: Sites like Unsplash are good, but try to opt for original images and graphs you took/made yourself for uniqueness and shareability

Image creation & upload checklist

Image SEO is largely about optimising your image files. Here’s a quick checklist to make sure you nail every aspect of your image file and achieve optimal performance:

  • Image file format:
    • Prefer next-gen formats such as WebP or AVIF. Use tools like Squoosh to convert your image into WebP.
    • JPEG is good for photos and images with lots of colours, PNG is good for logos and other simpler images.
  • Image filename:
    • Name the image file using descriptive text with relevant keywords towards the beginning of the filename. For example, “image-optimisation-checklist.webp” over “IMG435.webp”. Aim for a maximum of five words.
    • Don’t use abbreviations or include size specifications, and use hyphens to separate words in your filename.
    • Don’t rename an image file used in multiple posts or pages.
  • Image file size:
    • Images play a pivotal role in page speed. So, compress images for faster page load speeds. Use a tool like ImageOptim or to optimise the file size without having any noticeable compromise in quality.

Anything less than 100 KB is considered a good image file size. However, Google doesn’t look at each individual image size, rather, the total page size.

So, if you have a small image where quality differences aren’t as evident, then consider compressing that image even further so you have extra room to keep other, more important images bigger, especially if those images lose quality after compression.

  • Image properties:
    • Use responsive images for quick loading on mobile devices. If you’re using WordPress 4.4 or above, then this is already taken care of. If not, make sure your images have the srcset attribute that tells the browser to load different versions of an image for different screen sizes.
    • Write a descriptive, keyword-optimised alt text for better accessibility and help search engine crawlers better understand and index your image. Keep your alt text less than 125 characters and include your target keyword towards the beginning of the tag. Don’t use dashes in your alt text and avoid keyword stuffing.
    • Write a short, descriptive, catchy title that complements the alt text. If you use WordPress, the image title is usually the same as the filename so you can choose to leave it as it is. Make sure to include your target keyword.
    • Use a mixture of LSI keywords and describe additional details such as the location and time of the picture (if applicable) in the caption.
    • Write detailed anchor texts for internal links pointing to your images to provide better context to search engines.
  • Image placement:
    • Strategically place images across your content for better engagement. Try to place images near relevant text. If you have an important image or an image that you wish to rank, place that near the top of the page.

If you’re using images to support a blog post, it’s good to have relevant images every 300 or so words to break up the text and improve readability. For ecommerce product pages, having multiple prominent images from various angles along with the ability to zoom in/out is a must.

Post-upload optimisation checklist

So your image files are ready. Once you upload them, what next?

Well, there are some advanced strategies you can implement on your website to take your image optimisation to the next level. Here’s a checklist to tick off:

  • Use image Schema

Google suggests “if you have images on your site, you can help users identify the type of content associated with the image by using appropriate structured data on your pages. This helps users find relevant content quickly, and sends better-targeted traffic to your site.”

So, add the appropriate image schema markup (recipe, product, video) to your pages to display image badges in Google Images, and drive more traffic to your pages. See Google’s structured data guidelines for images.

  • Use Open Graph Meta tag for social sharing

If you want more social media exposure and engagement for your images, you need to use Open Graph tags (Facebook), Cards (Twitter), and the like for other social media platforms. With these tags, you can specify which image Facebook (and other social networks) will use when people share your content.

So, define your Open Graph (og:image) in your page’s <head> section to add context to your pages for search engines and add your desired image to the content displayed on social platforms when it gets shared.

  • Include images in your sitemap

By including images in your XML sitemap, you provide Google with more details about your images and the URL of images that otherwise may not be discovered by Google. If you’re on WordPress, the Yoast SEO plugin does this automatically.

You can also have a separate image sitemap containing URLs from other domains, unlike regular sitemaps that have cross-domain restrictions. This lets you use CDNs (content delivery networks) to host images.

  • Implement lazy loading for images

Lazy loading essentially defers the loading of images (or other elements) until they enter the user’s viewport.

Google says “lazy loading can significantly speed up loading on long pages that include many images below the fold by loading them either as needed or when the primary content has finished loading and rendering.”

However, if implemented incorrectly, lazy loading can make your images hidden from search engines, which is the last thing you want. So, instead of messing around with JavaScript, use a plugin like A3 Lazy Load to load essential images directly in the HTML, and implement lazy loading for all non-essential images.

  • Host images on CDN

A CDN stores a cached version of your images in multiple geographic locations around the globe, and serves your content from the server closest to the user. This significantly reduces the load time and thus, helps SEO.

So, sign up for a CDN like Cloudflare or KeyCDN to serve images faster, and set up a CNAME record to host images on your own domain. Verify the CDN’s domain name in Google Search Console so you can get notifications of any crawl errors that may crop up.

  • Leverage browser caching

Browser caching lets images (and other files) get stored in your visitors’ browsers. This means the images load faster for them when they visit your website again.

Install a plugin like W3 Total Cache or WP Rocket to enable browser caching by default and add the required modifications to your .htaccess file.

Bonus: Core Web Vitals optimisation checklist

By now you’re likely aware of Google’s Core Web Vitals (aka page experience) update that essentially entails three real-world, user-centric metrics meant to quantify key aspects of user experience:

  1. Largest contentful paint (LCP) measures loading performance.
  2. First input delay (FID) measures interactivity.
  3. Cumulative layout shift (CLS) measures visual stability.

As you can tell, your website’s images play a major role in determining how well your pages fare in terms of these metrics. So, check off this list:

  • LCP Optimised

Images in the form of hero images, product carousels, etc. are frequently the largest contentful element immediately visible to users on many websites. To improve LCP, you essentially need to optimise image loading time.

So, use the above image speed optimisation tactics — using a CDN, caching, compression, next-gen format, etc. — to ensure blazing load speeds.

  • FID Optimised

FID considers the delay (in ms) users experience when trying to first interact with your page, such as clicking on a menu button or checking a checkbox.

So, as much as possible, avoid having large images above-the-fold, and prefer text or other simple elements that enable instant interactivity.

  • CLS Optimised

Imagine you’re trying to scroll down a page to read an article but accidentally click an ad that pops up — a frustrating experience that’s caused by layout shifting. CLS measures this layout shift: how the various page elements move around in the viewport as the page finishes loading.

To minimize this, include size attributes (width and height) for all your images, and reserve space for dynamically injected content such as ads with inline critical CSS. Use responsive images with the same aspect ratio for all sizes.

Google’s PageSpeed Insights provides actionable recommendations on optimising your images (and pages) for CWV.

Wrapping up

And that’s a wrap on our definitive image optimisation checklist. From beginner to advanced tactics, we’ve tried to cover all the important points that have the biggest impact on your image SEO.

Here are the key takeaways:

  • For each page, think about relevant, original images (photos, graphs, screenshots, etc.) that complement the text and encourage uniqueness and shareability.
  • Opt for modern image formats like WebP and AVIF.
  • Write a descriptive filename, alt text, title, and caption for each image, including the primary keyword.
  • Optimise the file size of all images for speed using an image compression tool.
  • Add images to your XML sitemap, structured data to your images, and Open Graph and Twitter Card tags.
  • Use a CDN, and implement lazy loading (correctly) and browser caching.
  • Check your CWV score using PageSpeed Insights and optimise your images for them.

Start by getting your free SEO audit report, and then work on these individual aspects to nail your image optimisation. That’s about it!

Found this post useful? Be sure to share the infographic checklist with your network. Need professionals to manage your SEO, images and otherwise? We’re here to help.

Image SEO checklist Supple

Enter Your Website & get an instant SEO Report for FREE