One view might be that the picture as interpreted is evidence of what it depicts and, since the technology collects and stores data from the real world, the resulting picture is a definition of what the camera was pointed at, and so denotational. Adopting the classification of Charles Sanders Peirce, this would be considered an indexical sign, i.e. there is a direct connection between the signifier and the signified. While it is true that an unedited photograph may be an index, digital technology is eroding the viewer's confidence that the image is an objective representation of reality.