title: Hold (lock) zoom or set zoom based on image size in Matlab
body: <p>I need to plot two figures and some points over it. The points can be outsize the image region, this makes Matlab to "autozoom" to fit the plotted points. The problem is that this makes difficult to compare the two images since the zoom is not the same for both images. So, how can I:</p>
  
  <ol>
  <li>hold / lock the figure zoom, so I can lock it after adding the image and before plotting the points.
  or</li>
  <li>set the zoom based on the image size (a percentage).</li>
  </ol>
  
  <p>Sample code:</p>
  
  <pre><code>imshow(myFig1);
  hold on;
  % Here I need to hold/lock the zoom or...
  plot(myPoints1(1,:),myPoints1(2,:),'+b');
  % ... or set here the zoom based on a percentage of the image size
  
  imshow(myFig2);
  hold on;
  % Here I need to hold/lock the zoom or...
  plot(myPoints2(1,:),myPoints2(2,:),'+b');
  % ... or set here the zoom based on a percentage of the image size
  </code></pre>