How to get a screenshot?

[Eric House <fixin@peak.org>]

I want to take a screenshot of a window running under X and eventually
to convert it to a .gif file.

I assume the Gimp can handle the conversion.  But how does one get a
screenshot under [Debian] Linux?  Is there anything comparable to
Snapshot (on Solaris), for example?  

Thanks,

--Eric House

+-------------------------------------------------------------------------+
|            from the desktop of: Eric House, fixin@peak.org              |
|    "The instructions said 'Win98 or better' -- so I installed Linux"    |
+-------------------------------------------------------------------------+