Its still not working but I think I know why. From reading the source code it looks like your signature is referencing the web page that the image is on and not the actual image itself.
Just go into your profile and paste this in:
(img)http://communities.msn.com/_Secure/0MgCvGfwP1omz9Kg7GL1I9LMX5PDP2887zbCAyr4KoQzRlprARGC64VCvpiU*cAjQDTGDv6URCTXOim!jNvmQsg/1256.jpg(/img)
Then change the () to [] like you did before.