@blackbird71: Same. The large "thumbnails" (i.e. featured posts) also work as well as the video thumbnails. It's baffling because these video thumbnails are really just regular image thumbnails with another image (play button) layered over them. Why didn't anything happen to their "src" tags? No idea...
I'll keep investigating.

@rif: You may have to go back down to 12.14... Seems like craigslist did something that made it break in Opera 12.16 because there haven't been any Opera 12 updates.

Craigslist is now working fine since going back to 12.14 (32-bit). Again, this is on Windows 8 x64.
I was having issues with 64-bit versions of Opera crashing often, so that's why I went back down to the 32-bit one.

My concern now is that I'm still having troubles as of very recent with the Gawker sites (like Jalopnik.com).
I'm trying to figure out exactly what the issue lies, but the thumbnails on the main pages are never loaded. For some reason, the "src" attribute (and only this one attribute) in each "img" element is not even downloaded in the main HTML page. Content blocker on and off - same deal. Same with masking as other browsers. Seems like something is getting screwed up with the HTTP request but I have to look more into it.
Also, the Login and Notification buttons (on the top left) are not working either but they did just revise the site so they may have broken it themselves too.

Anybody want to confirm this?

I've been having this same issue for ~1 week now.
Discovered the grid view recently (for car shopping and the view buttons on Craigslist worked, but now they don't do anything anymore.

12.16 x64 on Windows 8

I'm actually going to download 12.14 now because I've been running into a lot of such troubles recently with Opera.