There doesn't exist a native way of doing that on the network. However, as already mentioned in Schrödinger's cat's answer, you can use the image search option with Google, targeting this site via
Note though that this may only be valuable in select instances where posters did use images. Some threads only post an image in the ...
One thing one can do is to perform a Google image search for
site:tex.stackexchange.com <search term(s)>
I am using this sometimes to find possible duplicates, and, according to my experience, this turns out to work surprisingly well.
Actually, I sometimes wish that users asking questions could do that search themselves. If they end up not ...