I can try. It's a flat picture that usually shows a three-dimensional object. The object often appears over exposed, that is to have too much light on it. A hologram is transparent. There can be shadows and highlights. Backgrounds of holograms are usually darker than the object.

Computer holograms can be made so they turn, as in turning an object in your hand. There are also holograms that are not on a computer but more like a flat photograph and appear to move when someone walks by them. I might suggest that it could be similar to one bright spot of light that has been overlaid upon a second bright spot of light, but imperfectly so that one is aware of both spots. Again these would be in the middle of a dark background.

Weird glowing rainbow coloured picture of something that looks like it's a solid object behind a piece of glass, but in fact it's just a flat sheet.