I use image shack. It isn't too bad of a process to do really
Click on the link here
http://imageshack.us/
Then click on Browse and a window will pop up
Then you will have to click on the resize image and sometimes if it is too big for SR then you will have to resize it.
After that click host it
Once it works and a new page opens then go to the bottom of it
and then you will have to copy that link and then paste it on your signature
such as [IMG]LINK HERE[/IMG]
If you can't do it you would email me and I will try to assist you further. Let me know if that helps ok.