When it uses photographs, this method of sticking various images on one surface is called "photomontage"
Such framed, picture-like, wood-relief collages offer the artist an opportunity to 
explore ... Other methods for combining pictures are also called photomontage, 
such as... [DOC] [TLE] Layers of Meaning - PhotoPedagogy [PAR] An introduction to experimenting with Collage and Photomontage ...