In one of my Yahoo Groups today, I saw an attachment that was "IMSTP.GIF"

I didn't open it, of course, (I'm new to the boards, but not to security), but I just would like to know what it is. Web searches on it are not helpful what-so-ever.

Is it some sort of web bug? If so, I'm afraid to report it to Yahoo as they may take the entire group down.