I was having a very similar problem, Bugzy, which just started yesterday. Same thing as you; notifications took me to the new subscribed threads page, couldn't access the notifications at all, no one's avatar was showing up, I couldn't access the photos in my photo album, etc. Had the same problem whether I used Google or Firefox. Tried all kinds of things throughout the day, including turning off my ad blocking software (UBlock Origins). That didn't work earlier in the day, but finally yesterday evening while I was trying different solutions, I turned off the ad blocking software again, and this time it worked. It wasn't enough to add this site to the whitelist on the ad blocking software; I had to turn UBlock Origins off in order to make the site work correctly.
With more than one of us having this problem, not to mention other problems experienced by other members, it seems obvious that there's been some sort of changes made to the site that is affecting the way some of us are accessing it. I definitely don't like the idea that I'm being forced to turn off my ad blocker just so I can use the forum properly.
"No matter where you go, there you are."