Hey ,
I'm sorry mate but I come from Poland and it's a litlle bit difficult for me to understand this how you did the first one ------>
1.Upload your picture at photobucket.com or another image webhost.
2. Copy the HTML-code for the pic you want to use
3. Click on the image with the litle tree
A small box will pop up, there is a section called "image-URL", paste the HTML-code here and press the button marked "insert"
4. Now you just have to write any text you want to acompany your picture and press "post"

Pic in signature and Avatar was really easy