Just though that motion users by be interested in that you can hook some
consumer digital cameras
up to linux boxes via USB using gphoto2: http://www.gphoto.org/doc/remote/
I currently have a Nikon 5900, a 5 megapixel consumer digicam, that is
triggered by the on_movie_start
that calls a gphoto2 scripts that captures a high resolution still picture,
renames it and moves it to a folder.
I picked up the camera cheap off ebay (under =A320) because it has a broken
Got an AC adapter + USB cable and then after some entertainment getting it
into PTP mode, it works fine.
It's hidden away in a box with a hole for the lens to make it less obvious.
I figured that leaving a digicam in full view wouldn't be a good idea :-)