Collage Template Set.
Instructions: Open PSD files in Photoshop, Elements or Paint Shop Pro. Click on bottom layer. Paste your images above bottom layer, but below Mat layer(s). Rotate and size behind mat openings. Zoom in to make sure green does not show. This ensures your image is larger than the opening. Erase/Delete excess image, so it won't show up above other images. Save. Flatten before resizing.