show cv2 image in jupyter notebook code example

Example: images from opencv displayed in blue

# matplotlib interprets images in RGB format, but OpenCV uses BGR format

# so to convert the image so that it's properly loaded, convert it before loading

img = cv2.imread('filename.ext')		# this is read in BGR format
rgb_img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)		# this converts it into RGB

plt.imshow(rgb_img)
plt.show()