title: How can I quickly change pixels in a image from a color dictionary?
body: <p>I have an image, I want to change all the colors in the image from a color map eg. {(10,20,212) : (60,40,112)...} </p>
  
  <p>Currently, I am reading the image OpenCV and then iterating over the image array and changing each pixel, but this is very slow. </p>
  
  <p>Is there any way I can do it faster?</p>