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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John Mueller Hangout Transcript
John (Submitted Question) 43:52
Would a query string at the end of an image source URL have a negative effect for SEO, we use it for cache invalidation when an image is edited.
John (Answer) 44:01
So no, it wouldn’t cause issues with regards to SEO. But with images in general, we tend to recrawl and reprocess them much less frequently. So that means that if you’re regularly changing the image URLs linked in your website, we would have to kind of refine those again and put them in our image index again.
And that tends to take a lot longer than with normal HTML pages. So from that point of view, if you can avoid doing that too often, I would recommend doing that. If it’s something that happens, I don’t know very, very rarely and where you’re saying well, it doesn’t really matter too much how things are processed in image search, we don’t rely on Image Search for traffic to our website.
Then from that point of view, that’s totally a non-issue. The thing I would avoid, especially here with image URLs, is that you embed something that changes very quickly. So something like a session ID, or just like always today’s date, because that would probably change more often than we would reprocess the image URLs, and then we would never be able to index any of the images for image search.
