This scripted object plugin will bring you a new object primitive called 'ImagePlane'. After creating and attaching an ImagePlane object to a (perspective camera), it will always directly face the camera and fill the entire camera view perfectly.
You can assign image textures to that plane, the result being similar to a viewport background image, but on a geometric plane that has a certain depth in the scene. This allows pushing camera-aligned images in front of or behind certain objects.
The image plane will adjust correctly to the camera FOV (taking image and pixel aspect into account), it will stay at the specified (animatable) distance to the camera, will always face the camera and fill the visible area 100% (unless you have used offset and scale to modify the plane). It is useful as a replacement for background images as the imageplane moves right in 3D space and can both occlude other 3D objects and be occluded by them. It can be mapped with a 100% self-illuminated material that has an image sequence in the diffuse slot and the corresponding alpha channel in the opacity slot; this can be displayed directly in the viewports and is quite useful for creating set extension layouts when combining real footage with CG, for example.