Software Showing Post Processing? Available?

[winnipegger]

Is there software out there somewhere that can show what exactly has been done to an image in the way of post processing? If that sounds confusing what I am getting at is,say by way of example, there is a rainbow in the photo, is there software to detect whether the rainbow has been added in digitally or was really there in the first place? I know lots of photo contests say that there can be do "digital manipulation", but how would they know?
Just curious?

 

[Musicman]

I know lots of photo contests say that there can be do "digital manipulation", but how would they know?

They'll ask for the original RAW file if you win.

e2a: To answer your other question, there are people out there working on the idea.

Mostly, it's down to experts having a look at pixel level, from the stories I've seen in the press.