I found a way to make Image Search work! Masking as Firefox didn't work, so I assumed IE wouldn't either -- but today I checked just in case, and it does. Select "Mask as Internet Explorer" under site preferences. The camera icon will appear, and so far it's working fine for me.

(To be specific, what I'm talking about here is the search-by-image function, a.k.a. reverse image search. That's what Google blocks in Opera for some reason. The regular text search for images works in any browser.)

Ah! Found the problem. It wasn't Google itself, it was the extension I was using to disable Google's URL aliasing. (They quietly started doing that a while back. If you copy a link from a Google search page, you no longer get the URL of the site itself, you get a Google redirect to it. Very annoying.) That extension still works, but for some reason it now forces new tabs. I wonder why.

That said, Google Image Search definitely has deliberately been blocked in Opera. It was possible for a while to get around it with a custom search, but they've "fixed" that. Not even masking as another browser works. I'd still be very interested in a solution to that problem.

Google seems to be doing its best to break compatibility with Opera (at least v12). Image Search is no longer working, and regular search has decided it will always open search results in new tabs. If your preferences say not to do this, it ignores them. Anyone have a fix?