Turn images into a pixelated 3D scene with Cubify
CubeSter is an add-on that takes an image and creates an object from it, where the height of the mesh is based on the intensity of the pixel at that point. The object can either be composed of a bunch of blocks or of a single plane, giving some very neat results. Materials are automatically applied either by using an image or using vertex colors.
A while back an add-on called Cubify was released. It took and image and converted it into basically a height map. It was very slow once the image got above the size of about 32x32 though. CubeSter has the same basic ability, but runs about 1,600 times faster, meaning images with over 450,000 blocks can be generated in about 30 seconds.
The object can either be colored via vertex colors, or through an image. The object is also UV unwrapped when created, which allows for more flexibility when adjusting materials.
Side note: if using a laptop, try plugging it in. In my experience this can decrease the time it takes to generate the mesh by around 140%.
Here's a quick test I did on a picture I took in London last year: