Create a png, useful for web applications

#!/usr/bin/env python
import sys
import numpy as np
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt

def r():
    plt.ion()
    fig = plt.figure(1, figsize=(11.6,8.2))
    plt.hist(np.random.rand(100))
    fig.savefig('test.png')
    # fig.savefig( sys.stdout)

if __name__ == '__main__':
    r()