title: Image pixel coordinates
body: <p>I'm using PHP and ImageMagick to read colors from an image's edge. </p>
  
  <pre><code>$x = 1;
  $y = 1;
  $pixel = $image-&gt;getImagePixelColor($x, $y);
  $colors = $pixel-&gt;getColor(); // rgba
  </code></pre>
  
  <p>But I don't quite get how the coordinates work. So I created this 4px png.</p>
  
  <p><a href="https://i.stack.imgur.com/RAx7l.png" rel="nofollow"><img src="https://i.stack.imgur.com/RAx7l.png" alt="enter image description here"></a></p>
  
  <p><code>1,1</code> gives <code>rgba(0,30,255,0)</code> instead of the transparent pixel. Also, what if I select a large range of pixels?</p>