I use this one:
HoverSnap v0.8 :
HoverSnap is a a free handy snapshot tool with jpg, png, bmp and gif support.HoverSnap can take snapshots of the full screen, active window or a selected area. It can even capture layered windows (alphablended ones under 2K / XP). You can even FTP upload your screenshots !
You can set up the capture folder / filename and format.
You can reduce the capture size.
Auto-generate filename option will add the time stamp (date/time) to your filename in order to be able to take several captures without having to change the filename.
Optional sound when capture is done.
HoverSnap is FREE for personal use only
Screenshot:
Download link (direct)
it's around 400kb... not that much more