[londons_explore]

Nothing stops you editing the photo, printing it out, and taking a photo of the printout.

The new photo would still get signed, and look original.

And if you did this in the right conditions, it wouldn't be possible to tell it was a photo of a print.

[quonn]

Since all the metadata (exposure time, shutter speed and so on) in the photo is signed as well, it would be possible to tell.