I've been converting DA stock photos into 3D by creating layers and shifting them, then pulling parts of the photo right or left to give the appearance of forward or backward. Essentially, it's like cutting out part of a photo and visually moving that 2D cutout piece forward or backward. Think of it as stacked flat layers. Unfortunately, unless the composition or subject of a photo is shot a certain way, it LOOKS like a stack of flat layers, not a 3D photo. The exception is a shot that, visually, creates its own layers. See "Red Shoes" in my favorites. Visually, it would be easy to isolate the front leg, a middle area and the head/arm. I'd love to make a version of it, because it would truely appear three dimensional.

On the other hand, compare my flat posts to "Barbarella" (Headless Bill) in my favorites. That shows just how amazing a 3D photo can look when it's shot from two angles. Of course, you'll need the cyan/red glasses for that one, too.

For a 3D with real dimension, you need two photos taken about three inches apart. Once they're merged, you get a true 3D image when viewed through the correct glasses.