Each the size of a deck of cards. Most Digital Cameras have a shutter delay before you actually take pictures. Uses Compact Flash. Picture quality is lacking for a 2.1 Mega Pixel. It's physically too small.
Picture quality suffers.
Nikon Cool Pix 990. They just screw onto the front. The 35 to 105 lens becomes a 70 to 230 lens, 8mm 180 degrees side to side. Most inkjets are 8.5x11, they'll print 8x10 or smaller. Most are using these for pictures of family around the home, although a lot now take them on vacations.