Minimal code for rendering a numpy array as an image in a Jupyter notebook in memory. Borrowed from the Deep Dream notebook.

showarray.py

# python3
from io import BytesIO

import IPython.display
import numpy as np
import PIL.Image

def showarray(a, fmt='png'):
    a = np.uint8(a)
    f = BytesIO()
    PIL.Image.fromarray(a).save(f, fmt)
    IPython.display.display(IPython.display.Image(data=f.getvalue()))
    
showarray(np.random.rand(300, 700, 3) * 255)

# # python2
# import PIL.Image
# from cStringIO import StringIO
# import IPython.display
# import numpy as np
# def showarray(a, fmt='png'):
#     a = np.uint8(a)
#     f = StringIO()
#     PIL.Image.fromarray(a).save(f, fmt)
#     IPython.display.display(IPython.display.Image(data=f.getvalue()))