Tilt-shift photography uses a special lens to give real-world scenes the appearance of miniature models. Still images can be tilt-shifted in Photoshop by adjusting a photograph’s contrast, colour saturation and depth of focus.
Fine art search engine Artcyclopedia recently applied the technique to the paintings of Vincent Van Gogh, to fairly spectacular effect.
There’s a 16 image gallery including Starry Night (above) here.
None of these paintings has been added-to or removed-from or had its proportions changed. The effect is achieved simply by manipulating the light in the scene and adjusting the areas of the image that are more and less in focus, as you will see.