seo – How does hash in file name affect google image search ranking?

On a long-term basis, I don’t think there will be any differences in SEO impact (image-SEO) between the above two methods.

But, there could be short-term SEO impacts when changing filenames during updates.

Google is known to remove non-existent resources from the index after some delay (you can call it a grace period). Whenever you update an image, Google could take some time between de-indexing the old one and indexing the new one.

My suggestion is this:

Maintain filenames (to prevent short term SEO impacts mentioned earlier) with appropriate cache-control headers (for better user experience). You can set the max-age to a reasonable time depending upon a tentative update time in the future and can add must-revalidate directive. By this, whenever an image changes, the browser would pick the latest from the server. Otherwise, guided by max-age, the browser can use the cached copy.