I see, I remember having the same error before as well ... but I can't for the life of me remember what the work-around was (sucks getting old!) ... but I do think it had to do with pic size ... try a small pic (file size) and see if it uploads .. you don't actually have to post it ...
... hmmm actually, I just tried and I am getting the error now too! I can't even attach it ... well I guess you were spot on ... site admin needs to handle this.