With the Theft of Mobile Phones, and Digital Cameras on the increase, manufacturers should be doing something to prevent it, or at least make the resale of such products difficult. I do not believe that it is beyond the wit of man to be able to permanently embed the serial number and model of the device inside the image that it produces. Many stolen digital cameras and mobile phones will (after theft) be used, in the manner that they were intended and their resulting images will be posted on the internet.
Why not, using a search engine, then let the authorities, be it the Rozzers, Feds, Insurance companies trawl the internet searching for the serial numbers of stolen devices. I certainly believe that the good people at Google would (just for the resulting good publicity) be happy to modify their search algorithms to enable select agencies to carry out the search, and return appropriate information very quickly. Whilst there will always be the hard core thieves that will attempt to undo/crack or otherwise tamper with the embedded details, a great many would not have the ability to, or indeed think of trying to break the system.