Probably not a good idea to keep images stored on any device that can be linked to you. If nothing else, it sounds like having these images recovered by authorities could possibly lead to a warrant to search you, your car, or your home based on suspicion of manufacture/probable cause. If you're wanting to keep these kinds of images on hand, consider putting them on something like a flash drive or a CD-ROM. In the event of an emergency, you can toss those in the microwave and quickly destroy any damning photo evidence.