Spot the difference between the ear with the hearing aid and the one without, eh? Well it's certainly hard, but if you look closely:
There, you can just about make out a clear plastic tube running up out of the ear on the right. The rest of the image looks pretty much the same, though.
Hmm ... perhaps a little too much the same?
Here are the two images showed fast one after the other. It's a bit jumpy, because I can't be bothered to spend ages lining it up just for you, but you can see what I mean:
Apart from the clear tube and two swatches of hair, everything else is the same. When putting the hearing aid in (or taking it out), no other hair was displaced. Only the hair that might get caught in the picture when cutting the thin tube from one image and pasting it into another moved. If you look closely enough, you can even see a rectangular boundary.
So there you go, you've spotted the difference: the image on the right has been photoshopped and the image on the left hasn't.