I was messing around with PIL (Python Image Library) and created a simple image based on random colors.
from PIL import Image
import random
import operator
width = 100
height = 100
data = []
start = (random.randint(0, 255), random.randint(0, 255), random.randint(0, 255))
for x in xrange(0, width*height):
rand = (random.randint(-5, 5), random.randint(-5, 5), random.randint(-5, 5))
data.append(tuple(map(operator.add, start, rand)))
start = tuple(map(operator.add, start, rand))
img = Image.new('RGB', (width, height))
img.putdata(data)
img.save('image.png')
(first two images use -1/1, last two use -5/5)