Display MNIST image using matplotlib [duplicate]

Question

I am using tensorflow to import some MNIST input data. I followed this tutorial...https://www.tensorflow.org/get_started/mnist/beginners

I am importing them as so...

from tensorflow.examples.tutorials.mnist import input_data

mnist = input_data.read_data_sets("/tmp/data/", one_hot=True)

I want to be able to display any of the images from the training set. I know the location of the images is mnist.train.images, so I try to access the first images and display it like so...

with tf.Session() as sess:
    #access first image
    first_image = mnist.train.images[0]

    first_image = np.array(first_image, dtype='uint8')
    pixels = first_image.reshape((28, 28))
    plt.imshow(pixels, cmap='gray')

I a attempt to convert the image to a 28 by 28 numpy array because I know that each image is 28 by 28 pixels.

However, when I run the code all I get is the following...

Clearly I am doing something wrong. When I print out the matrix, everything seems to look good, but I think I am incorrectly reshaping it.

Answer 1

Here is the complete code for showing image using matplotlib

from matplotlib import pyplot as plt
import numpy as np
from tensorflow.examples.tutorials.mnist import input_data

mnist = input_data.read_data_sets('MNIST_data', one_hot = True)
first_image = mnist.test.images[0]
first_image = np.array(first_image, dtype='float')
pixels = first_image.reshape((28, 28))
plt.imshow(pixels, cmap='gray')
plt.show()

Answer 2

The following code shows example images displayed from the MNIST digit database used for training neural networks. It uses a variety of pieces of code from around stackflow and avoids pil.

# Tested with Python 3.5.2 with tensorflow and matplotlib installed.
from matplotlib import pyplot as plt
import numpy as np
from tensorflow.examples.tutorials.mnist import input_data
mnist = input_data.read_data_sets('MNIST_data', one_hot = True)
def gen_image(arr):
    two_d = (np.reshape(arr, (28, 28)) * 255).astype(np.uint8)
    plt.imshow(two_d, interpolation='nearest')
    return plt

# Get a batch of two random images and show in a pop-up window.
batch_xs, batch_ys = mnist.test.next_batch(2)
gen_image(batch_xs[0]).show()
gen_image(batch_xs[1]).show()

The definition of mnist is at: https://github.com/tensorflow/tensorflow/blob/master/tensorflow/contrib/learn/python/learn/datasets/mnist.py

The tensorflow neural network that led me to the need to display the MNINST images is at: https://github.com/tensorflow/tensorflow/blob/r1.2/tensorflow/examples/tutorials/mnist/mnist_deep.py

Since I have only been programming Python for two hours, I might have made some newby errors. Please feel free to correct.