Get a raspberry pi and a raspberry pi camera board. With them, you can do lots of high level stuff from triggering time lapse photos to on the fly image processing with opencv. Or, you could get a serial camera module and SD card shield for the arduino, and take photos that way too. That would probably be a little easier, but less powerful.
This would answer your question: TTL Serial JPEG Camera with NTSC Video : ID 397 : $39.95 : Adafruit Industries, Unique & fun DIY electronics and kits