Ok. You are going to need an image hosting site to do this. Something like photobucket, image shack or flckr.
First upload the picture you want to use to the hosting site. Next, copy the IMG Code link and just copy and paste to your text box under edit signature. If the hosting site does not have a IMG Code you will need to copy the Direct Link line. It should looks something like this:
Now go back to Fin Heaven and goto user settings. I would suggest opening a new tab or window to do this. Once in settings click on signature. Once there type in the following: . Make sure there is no space between the front and back of the link and the brackets (these---> [ ] ).
This should work. It worked for me. I am hoping this is a temporary fix until the site is back to normal running parameters.