PIL compose thumbnail images

gistfile1.py

import Image

SPACING = 10

# Open source images
imgs = map(Image.open, ['1.gif', '2.gif', '3.gif', '4.gif'])

# Assume standard dimensions and store them
width, height = imgs[0].size
side_length = sqrt(len(imgs))
extra_space = (side_length - 1) * SPACING

# Create blank template image
background = Image.new('RGBA',
                       (width*2 + extra_space,
                        height*2 + extra_space),
                       (0,0,0,255))

# Compose images
background.paste(imgs[0], (0,0))
background.paste(imgs[1], (width+extra_space,0))
background.paste(imgs[2], (0,height+extra_space))
background.paste(imgs[3], (width+extra_space,height+extra_space))

# Save resulting image
background.save('out.gif')