I sat through a forensics seminar that was run by the NY State Police. They had a jpg picture of a car. They then showed the metadata. It had the GPS coord, the Iphone ser # as well as other damning data.

Basically if the bad guys aren't smart enough to scrub the metadata before posting "bad" pictures, then it's real easy for the good guys to catch them

Of course the Buffalo, NY PD got caught because they got rid of some copiers that had hard drives with images of all the evidence they photocopied over the years. So the "tech" can be bad or good for the "law."