Yeah, Google's reverse image search is unusable with Opera... unless you change the user agent string and tell Google you're using Firefox.

Then they whine about how Facebook and Apple are trying to destroy the open web.

Quick tip: On images.google.com, go to 'Quick preferences' (either F12 or right click on the page), hit 'Edit site preference', then set the user agent under the 'Network' tab.

I'm tempted to do this for all google related services, because they are such browser prudes.

It is a chicken and egg case, right? Without support, no increase in market share, and no market share means, no support. Hence it is sad that a big player like Google does this, in an apparent act of getting more people on to Chrome. If Google does no evil, they will support ( we all know they can ) the most standards compliant browser.

Opera was at 4% last time I checked. Has that changed? If not, I find it hard to believe that's the motive.

It has. Their market share was at 2% at the beginning of this year, and has now fallen to 1.7%. It's falling month after month. There's no reason to expect their market share will increase any time soon.

You are saying "is". I am saying "should".