I streched the images, but I repainted the lost detail (which is relatively easy when the surrounding already fits). But in most of the cases I simply tried to find images in the right resolution.
If you want to have camera movement applied to a shot, I would suggest a simple layering method. Foreground, midground, background on different layers (maybe 5 or 6). For a complex shot like that(with a midground reaching from a far to a near plane) or one with a more dynamic camera movement, you need to create more geometry than I did here, map your painted textures on it or even remodel the detail completely..