As well as the additional ranking opportunities that come from well optimised images, they also impact user experience and page load times, and with Core Web Vitals now an official ranking factor, it makes sense to make image optimisation part of your SEO strategy. Here are some key improvements to focus on:
Name your files properly
Your file name does more than just help you identify the right image from your own internal folders, it can actually impact how easy it is for search engines to interpret your image, so it’s worth the few seconds it takes to rename it before uploading to your site. Plus, a file that describes the picture and uses keywords is probably going to make your life easier than something like ‘IMG_011456’ from an organisational perspective.
If you’ve got a media library with thousands of the latter already in it, you might decide it’s not worth the time to go back through every single one, but it’s probably not a bad idea to consider for key pages and images, and as a good practice to get into going forward.
Compress your images
Huge images are one of the biggest factors behind poor site speed, and not only is this terrible for UX, it’s becoming increasingly more influential as a ranking signal. What’s more, it’s just unnecessary. A crawling tool like Screaming Frog will highlight any images over a certain size, and you can also use Google’s PageSpeed Insights tool to check your site speed, which will list the most offending culprits behind your poor score.
There are also various WordPress plug-ins available for image optimisation, such as Smush. These allow you to quickly compress your existing images while retaining quality, and will often do it automatically when you add any new images to your site.
Add descriptive alt text
The primary use of alt tags is to provide a text alternative to your images so that if for some reason they don’t load properly, the image box will show the alt tag which will explain what the viewer should be seeing. So it’s useful for user experience, but it can also hold benefit for SEO because you’re associating keywords with images. Just make sure you’re describing the image and not shoehorning keywords in for the sake of it.
Again, this is probably not something to lose sleep over if your site has 827 images and no current alt text, but it is a good habit to get into, and one to think about for your key service or product pages.
Use captions
Similarly, image captions (the text directly underneath your images) are also advised as best practice by Google. It claims to extract information about the subject matter from various content on the page, including captions, so it makes sense to consider this, especially in scenarios where you think it could be of particular use to your visitors.
Use high quality images
It sort of goes without saying, but really, one of the best ways to make sure the images you have on your site are doing their part and working as hard as they can, is to choose the right ones in the first place. If you can, try and avoid generic stock photography that’s already everywhere else on the internet. And make sure the image is relevant and of a high enough resolution. This obviously affects how your audience thinks of your site, and therefore brand, but in turn this also impacts the metrics that affect your SERPs, such as dwell time and bounce rate.
