If its for general interest/one-off:
Try ebay for faulty digital cameras. They can be had for under $5 US...usually with a broken LCD screen. It'll contain everything you need, but be prepared to do your research on the IC's inside, msot have standard interfaces on the PCB for manufacturing/programming purposes.
For commercial purposes I would advice buying a development board. Many DSP's can perform JPEG compression, but you may need a CPLD to interface the CMOS side. A lot of work but its certainly doable, even for the hobbyist.
Blueteeth