PostgreSQL function to crop images (uses plpythonu and python PIL)

postgresql_crop_image.sql

CREATE OR REPLACE FUNCTION crop(image bytea, rect box)
 RETURNS bytea
 LANGUAGE plpythonu
AS $function$
if ('io' in SD) and ('StringIO' in SD) and ('Image' in SD):
    io = SD['io']
    StringIO = SD['StringIO']
    Image = SD['Image']
else:
    import io, StringIO
    from PIL import Image
    SD['io'] = io
    SD['StringIO'] = StringIO
    SD['Image'] = Image
rect_list = [int(x) for x in rect.strip().replace('(', '').replace(')', '').split(',')]
rect_list = rect_list[2:] + rect_list[:2]
im = Image.open(io.BytesIO(image))
im = im.crop(rect_list)
f = StringIO.StringIO()
im.save(f, 'jpeg')
f.seek(0)
return f.read()
$function$