Uncroppable

Make your image uncroppable

The starting image :

The result : an almost identical image that can't be cropped

Let's crop it anyway :

Let's recover from it :

If we mixed the channels :

If we didn't mix the channels :

How it's done :

We steganographically encode a permuted half resolution image in the two least significant bits of each pixel channel.

For more see the commented uncroppable.py file

Of course, this is just a proof of concept that is easily detectable with the appropriate software, and any advanced uncroppable image algorithm would use error correcting code and the compression codecs directly in the hardware encoder of your sensor, to make it harder to detect.