Still trying (and failing) to add a pic of Penny to my signature. I added (or at least I hope I have) the url address of the pic I'd like to use. I also think I've added this string to my signature box, but no picture.
I don't think this was the problem but the link you used was to the web page not the actual image. I've changed that to point to the thumbnail instead and it all looks ok now (I did change something else and it seems to be a bug, I'll add it to the list to fix.)