I really love these 2.5D animations of classical paintings by Rino Stefano Tagliafierro. He says that they are "a tribute to the art and her disarming beauty." Some are more inviting and evocative than the actual painting. I want to keep getting into the scene. And a few are quite disturbing.
Rather than simple animations, Rino used layered animation to further immerse the viewer into landscapes, religious and mythological scenes.
Here's how this is done:
They processed each still photo in Photoshop, separating different elements on their own layers — parts of the background, elements of the figures, etc. Then they imported these still layers to After Effects, where they animated them in layers, moving them at sightly different speeds to achieve a parallax effect — since objects closer to the viewer appear to move faster than objects faraway, this makes your brain think the camera is moving in 3D space. It's the same parallax effect they used in old video games, when true 3D was still not available.
Then they applied some subtle deformation to some elements of the image (like the wings of that owl) to give the illusion of actual movement. Add some clever editing and boom, you think you are watching actual video captures.
The technique is getting more and more popular and, when it's not exaggerated like in some of the artwork in this video, I can't have enough of it.