I have a particular interest in 3D imaging. I have played around with generating 3D images by various means including completely by hand retouching a single 2D image. Here are some examples. The first three images started out as ordinary flat 2D images. I have manipulated the images to produce a false 3D aspect. In particular, the 3D version of my recent Orion astrophoto is purely speculative and not based in any observation. We are not able to detect any 3 dimensional properties of an object that far away even with the best telescopes.
All of the following images are intended for crossed eye viewing. If you aren't familiar with this you first must be able to cross your eyes at will. You then look at the center of the pair of images and cross your eyes until you see three images; one on the left and on the right and in the centre a third image that is the two combined. That is the image that has the full three dimensional aspect. Concentrate on it and ignore the other two images to either side.
This next image is not from a photo but is generated via a computer program from digital terrain altitude data from the Canadian Geophysical Service map database. It is the view from the top of Mt. Robson in Northern British Columbia looking down toward the southwest. All of the elements in the image are created by me as textures and are then applied as I chose to the blank 3D form of the landscape. I used textures obtained by photographing actual scenery in the locale of Mt. Robson and I try to make even the colour and orientation of the strata as accurate as possible.