Create set of random JPGs

Here's the scenario, I want to create a set of random, small jpg's - anywhere between 50 bytes and 8k in size - the actual visual content of the jpeg is irrelevant as long as they're valid. I need to generate a thousand or so, and they all have to be unique - even if they're only different by a single pixel. Can I just write a jpeg header/footer and some random bytes in there? I'm not able to use existing photos or sets of photos from the web.

The second issue is that the set of images has to be different for each run of the program.

I'd prefer to do this in python, as the wrapping scripts are in Python.

I've looked for python code to generate jpg's from scratch, and didn't find anything, so pointers to libraries are just as good.

Solution

If the images can be only random noise, so you could generate an array using numpy.random and save them using PIL's Image.save.

This example might be expanded, including ways to avoid a (very unlikely) repetition of patterns:

import numpy
from PIL import Image

for n in range(10):
    a = numpy.random.rand(30,30,3) * 255
    im_out = Image.fromarray(a.astype('uint8')).convert('RGB')
    im_out.save('out%000d.jpg' % n)

These conditions must be met in order to get jpeg images:

The array needs to be shaped (m, n, 3) - three colors, R G and B;
Each element (each color of each pixel) has to be a byte integer (uint, or unsigned integer with 8 bits), ranging from 0 to 255.

Additionaly, some other way besides pure randomness might be used in order to generate the images in case you don't want pure noise.