Change the file format, Its not working.
it's not working because SMF is garbage. save the image, then export it again with a bunch of different editors. if given the option, choose to save it with as little metadata as possible, because that seems to be what the forum software generally has a problem with
one of them will probably work eventually
but don't save it as a jpg because then it won't have any transparency
edit: joe's right, it works. I was assuming you got an error message. if you don't get an error message then there was no problem