Tch, dammit, Google.

Just when I thanked you for fixing something that was broke, you turn around, and fix something that wasn't broke.

Clicking an image to view it fullsize gets you a little thumbnail viewer thing, which is an imitation of the shitty way Facebook fucking does it.

Yeah, copy Facebook, brilliant.

And on 2 year old posts, it doesn't work at all.

Bypass it with right click, and "open in new tab".
Or new window for those with old browsers.