If there were a big enough set of images with serial number data associated to them, it would be trivial to link one image to another - which might be used as a profile picture on Facebook, or perhaps a picture on a dating site.
Being able to link the photos to the same owner could potentially lead to PII becoming available, and could lead to embarrassing, or potentially dangerous situations.
Being able to link the photos to the same owner could potentially lead to PII becoming available, and could lead to embarrassing, or potentially dangerous situations.