Just to be clear, the only mentioned program I am familiar with is photoshop (I've two versions, but they're essentially the same) and its, unless you steal it, not free. The other two, gimp and photoscape (I believe) are both free programs, but I've never used either of them and cannot comment on their individual abilities or if overlays are possible. There are, however, guys here who are - @green18 comes to mind - and may be able to offer you suggestions. Otherwise, you may want to spend a little quality time with Google to see if they (either/or) are even an option. Good luck.
Does this look like a sculpture to you? Do you see a face and conclude it's intentional? If so, you'd make an ideal "Coast to Coast AM" overnight syndicated radio listener. Last night, there was some yay-hoo, Richard C. Hoagland, winner of the Ignobel Prize, on with George who insisted this proves there is a massive number of humans living underground on Mars. Umm..., yah. We used to say any fraud can have a website, but now it extends to broadcast radio and TV too.