title: Combine 2-3 transparent PNG images on top of each other with PHP
body: <p>I am working on a custom avatar system for a project, but I have never really done much with the image side of PHP.  I assume I need to use GD in some way, but I have no idea where to even start.</p>
  
  <p>Basically, there are a bunch of pre-made transparent PNG images.  Users can select 2-3 of them to customize their avatar, and I want to be able to take these images and make a single image out of them to be stored in a folder.</p>