NEW BUG Post icon keeps disappearing

I've set the post icon via image url links the edit thread page several times now, and it's worked for a while, but as soon as I edit the OP / thread again it seems like the icon disappears.

I also noticed that since we moved the server, it's not possible for me to upload pictures directly to PC in the way we usually do it; I get an error message after clicking Upload. Perhaps these things are related?

Image Share stopped working because I forgot to install something. Should be fixed.

Edit: Nope. Will investigate further.