I have created an array :

import numpy as np
data = np.zeros( (512,512,3), dtype=np.uint8)
data[256,256] = [255,0,0]

What I want this to do is display a single red dot in the center of a 512x512 image. (At least to begin with... I think I can figure out the rest from there)

You could use PIL to create (and display) an image:

from PIL import Image
import numpy as np

w, h = 512, 512
data = np.zeros((h, w, 3), dtype=np.uint8)
data[0:256, 0:256] = [255, 0, 0] # red patch in upper left
img = Image.fromarray(data, 'RGB')
img.save('my.png')
img.show()

The following should work:

from matplotlib import pyplot as plt
plt.imshow(data, interpolation='nearest')
plt.show()

If you are using Jupyter notebook/lab, use this inline command before importing matplotlib:

%matplotlib inline 

Shortest path is to use scipy, like this:

from scipy.misc import toimage
toimage(data).show()

This requires PIL or Pillow to be installed as well.

A similar approach also requiring PIL or Pillow but which may invoke a different viewer is:

from scipy.misc import imshow
imshow(data)

Using pillow's fromarray, for example:

from PIL import Image
from numpy import *

im = array(Image.open('image.jpg'))
Image.fromarray(im).show()

import numpy as np
from keras.preprocessing.image import array_to_img
img = np.zeros([525,525,3], np.uint8)
b=array_to_img(img)
b​