Why won't banner upload?

[tikva]

I clicked on someone's banner, went to the site, put in my info, copied the BBC url/img, went to 'edit signature' in my user CP, pasted the img. Didn't work. Pasted the url. Didn't work. Pasted the url and img. Didn't work. Tried all the above with someone else's banner. Didn't work.

What did I do wrong?

EDIT: Never mind. It seems to be showing up randomly whenever it feels like it.....