IANAL, but I assume that if someone actually memorized a confidential document, rewrote it from memory, and showed it to people at another company, it would be equivalent to just walking out the door with the physical document in the eyes of the law. judges tend not to be amused by these kinds of logical gymnastics.

Not in that sense, no. I am sure no one on Earth would be able to reproduce a 600x600 pic identical to original.

It would be a life's work for anyone to memorize 600kb text only file.