Stoop - when in Photobucket and clicking on Resize I only get 4 options Avatar (100 x 75), Thumbnail (160x 120), Website, E-mail (320 x 240) and Message Board (640 x 480). I don't get the option to enter a particular size eg 400 x 400 as you suggest.
If it helps anyone else, these two pictures are in order, first full size and second Message Board (640 x 480). I think I'll use the Message Board size from now on