title: how to change DPI of an image in MATLAB
body: <p>Here is the problem to change an image resolution from 300 dpi to 200 dpi or 600 dpi. 
  i am using matlab but how can i be. so for i have use the imresize function which down sample the image and up sample it. </p>
  
  <pre><code> imresize(image, scale ,interpolation). 
  </code></pre>
  
  <p>how can down sample the image to reduce its quality too. so that i may check the difference between the original image and the down sampled image.</p>
  
  <pre><code>j= imresize(I,0.2,'nearest');
  </code></pre>
  
  <p>where I is the original image and j is the down sampled image. is this changing the dpi of an image.</p>