Places 3 6x4 photos onto an A4 sheet for printing. Can be configured to support other image sizes.
Usage: photo2A4.py [image1] [image2] [image3]
On Windows, this can be set up to run from "Send To". You can then select up to 3 images in Windows Explorer, select "photo2A4" in the right click "Send To" menu and the image will open in the photo viewer ready to print.