1) I tried a non-TinyURL copy of the same pic and that didn't work after several attempts, so I doubt it's that.
2) I had NINE pictures from the same location in my sig up until recently, so it's unlikely to be inage volume.
3) Almost all the pics in my sig at the moment are TinyURL pictures due to space constraints, so the mere fact that it's from TinyURL can't be the source of the problem. *goes to try again a few times*
EDIT : Like a good

, I've been doing some experimentation, and come up with some more facts -
1) After trying TinyURL code for the image in my sig, I had no luck.
2) After trying non-TinyURL code in my sig, there was also no luck.
3) After DELETING MY WHOLE DAMN SIGNATURE and using only the TinyURL code, it refused to work, so it's not a number of images thing.
4) After trying the non-TinyURL in an empty signature, it still failed.