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.)