Most all cameras support external memory. Some cameras even come with an 8Mb memory card. The Univeral Serial Bus Interface makes transferring photographs to your computer really fast. Only few digital cameras have a USB interface. Most others transfer photographs using a serial or parallel connection.
Serial connection is the slowest, as well as the most widely used.
When you have captured 200 to 300 tombstones photographs, and each photograph averages 50K in file size, you could spend an hour transferring photographs to your computer. With USB, all of the photographs will transfer in 30 seconds. But before you buy a camera with USB interface, make sure your computer has a USB port. USB ports seem to be standard on computers sold since the beginning of 1999. Prior to then, you need to check your computer.