I've seen some recent post concerning problems with this site. There are a few things apparently not working right now, such as most of the right column and maybe the sig system is down too. I tried it out yesterday and it worked for me but then other people are having a terrible time with a few features here that aren't giving me any trouble at all.
I'd say to keep trying every day and don't lose hope, it may not be a problem on your end.
Gif files are fine, I use one in my avatar. Most popular picture files work, but I'm not sure of Psd files.