[JacKTrocinskI]

Pretty sure Benford's law applies to images and can be used as a tool to detect fakes.

[MauranKilom]

Interesting idea, but it's not obvious to me in what way you would apply it.

For example, compositing two images that somehow obey Benford's law should result in something that also obeys it.

Maybe you mean "Benford's law" as in "just general stastical properties", but I hope you had something more specific in mind.