Sidewalls of a flash opening formed in a front cover of a camera are processed with the same surface treatment as that of the front cover. Such information can be used for various purposes, including identifying an image as originating from a particular source. The second ultra hard material layer has a thickness in the range of 0. The ignition material includes an energetic composition. The message can be a postal indicium. An expandable link extends between the second end of the first curved segment and the first end the second curved segment.