title: How to crop a large jpeg into smaller tile jpegs?
body: <p>For example, I have a big.jpg which is 600 (w) x 300 (h), I would like to crop it into 250 x 250 each. Such that <code>big.jpg</code> becomes 6 tile jpegs:</p>
  
  <pre><code>tile_0_0.jpg (250 x 250)
  tile_0_1.jpg (250 x 250)
  tile_0_2.jpg (100 x 250)
  tile_1_0.jpg (250 x 50)
  tile_1_1.jpg (250 x 50)
  tile_1_2.jpg (100 x 50)
  </code></pre>
  
  <p>Any tool (command line or GUI) to recommended? Thanks!</p>