In terms of cache optimization it is recommended for static files like images to cache them forever. In this case if you want to update an image you have to use a different file name so that the client browser downloads the new image instead of showing the cached one.
I don't cache image files. So if I update the file
myimage.png the file name remains the same.
I cache image files forever. That's why I use a hash in the file name.
File name before update:
File name after update:
Am I right that file names without hashes are way better in terms of SEO?