Images
Images are used on websites to provide more engaging experiences for users, while also presenting more information about a topic. While positive for user experience, images can cause issues for a website’s SEO and performance. Our key takeaways from Google’s ongoing SEO Office Hours sessions cover more insights into the impact of unoptimized images, as well as best practice recommendations from Google.
For more on website content best practices for SEO, read our Guide to Optimizing Website Content for Search — or explore our Website Intelligence Academy resources on SEO & Content.
Google Chooses a Higher Resolution Image Where Multiple Versions Exist
If you have both high and low resolution versions of images, Google will prefer the higher resolution version.
Image Sitemaps Help Google Understand Which Images You Want to Be Indexed
Google can find images to index in the source code, but Sitemaps can help them to confirm which images you want to be indexed.
Unique Images are More Likely to Generate a Link to Your Pages in Google Image search
Google image search will de-deuplicate images used on multiple websites and only link to a single page with the image, so a unique photo can be shown separately.
Alt Text Helps Google Understand Pages Beyond Image Search
Text in the alt attribute of images is seen as text on the page and can help Google better understand the page a little bit better beyond image search. However, the text in the alt attribute will likely be somewhere on the page anyway.
Image Aspect Ratio Important For Some Types of Structured Data
Image aspect ratio can be important for some types of structured data and rich results like recipes. John recommends following Google’s suggested image aspect ratio and minimal size.
Check Alt Text is Present on Mobile Version of Images
John recommends checking that the alt text is present for the mobile version of images for mobile-first indexing. This is something Google has seen missing from sites that serve different content on mobile.
Avoid Using Lazy-loading For Crucial Images & Content
If you have images and content that are essential to the website, then avoid using lazy-loading for these elements as Googlebot isn’t always able to process them.
Image URLs Can be Flagged as Soft 404s in GSC
The GSC Index Coverage report may flag image URLs as soft 404s if they have a non-standard image URL. This is because they are seen as a 200 page without any HTML.
GSC Inspect URL Tool Shows How Pages Appear for Web Search Not Image Search
If you’re seeing errors when testing image URLs in the GSC Inspect URL tool, this is because the tool only shows if results appear in web search and doesn’t reflect what is happening in image search.
Lazy-loading Images Can be Implemented Using Noscript Tags and Structured Data
For lazy-loading images, it is important for Google to be able to find the image source tag on the page. This can be implemented using the noscript tag or structured data, so even if Google doesn’t see the images when it renders the page, it knows that they’re associated with the page.