That's correct. Supporting Members can play with 125 by 125.100 by 100 I believe.
That's correct too.edit: Actually that seems to have changed. Now you can upload any size and the forum software will resize it for you.
The software resizes the pic for you according to your user group limits.
Another correct assumption.i thought you had to be a supporting member (or green or special blue) to access that area
Supporting Members have that option as well as SB Staff. There also are few members with a custom user title but they've had that for a few years. There was a period a few years ago when it was enabled for everybody.