Your camera is snatched. Will you ever see it a-gain Probably not. But it may send postcards from its new owner. The【C1】______of recovery of lost or stolen cameras have improved【C2】______newer devices combined with online photo-sharing services create a digital track one can【C3】______with the right tools. Dozens of cameras from major manufacturers【C4】______the serial number found on a camera"s body into its software as well. The serial number is then included in the metadata with which every picture taken by the camera is tagged. When a photo is uploaded at sites like Flickr, they can, therefore, be【C5】______and indexed. Mr. Westin"s company, which makes the Gadget-Trak theft-recovery applications, has begun to create a searchable image database for lost cameras. When the owners upload the tagged photos they provide the【C6】______link. Once the database is established, the company will compare it with that of a list of missing serial numbers【C7】______by police. Of course, even if a camera"s serial number crops up,【C8】______the device"s current location need not be【C9】______. However, there is also good news: posted pictures may give clues【C10】______its current location. Even more helpfully, more and more cameras now come 【C11】______a GPS receiver for inserting geographical coordinates into a picture"s metadata. Flickr won"t show the uploading account holder such information【C12】______a user explicitly permits it. Photos posted in other ways, 【C13】______, may leak this information more casually. With enough such【C14】______, police could ask a photo service or obtain a(n)【C15】______to retrieve location data stored in the user"s account. Mr. Westin says that photographers can examine an image taken by their camera【C16】______losing it and extract the serial number. He wants to release a tool to make this【C17】______. All this is, of course, a double-edged【C18】______. Any information that helps find stolen 【C19】______may also be used to track camera owners" activities. Tools to【C20】______such data before photos are uploaded to the internet are available. And thieves know it.