title: rgb of an image
body: <p>To get RGB values:</p>
  
  <pre><code>RGB = imread('C:\Documents and Settings\student2\Desktop\Water lilies.jpg');
  R = RGB(:, :, 1);
  G = RGB(:, :, 2);
  B = RGB(:, :, 3);
  </code></pre>
  
  <p>Can someone tell me why we use 1, 2, and 3 to get Red, Green, and Blue matrices respectively?</p>