One SEO Professional was concerned about query strings at the end of image source URLs.
They asked John Mueller whether this would have a negative effect on SEO, because they use it for cache invalidation once an image has been edited.
John answered that no, this would not cause any issues for SEO. In terms of images in general, though, he said that they do tend to re-crawl and re-process them much less frequently when compared to other media.
If you are changing image URLs that are linked in your site, they will have to refine these images once again and add them to their image index.
This process is something that takes longer than with normal HTML pages. Therefore, if you can avoid changing image URLs too often, John would recommend doing that.
If this process is something that happens rarely, or your site doesn’t depend on image search to bring traffic, then you shouldn’t worry too much about query strings on the image source.
From this perspective, it’s a non-issue. The one thing that John said he would avoid, however, especially with image URLs, is embedding something that changes quickly.
Something like a session ID, or something like today’s date, because of how often this changes, Google would simply reprocess the image URLs, and then they will—essentially—not ever be able to index the images for image search.
This happens at approximately the 43:52 mark in the video.
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