title: How to create watermark with imagemagick
body: <p>I'm trying to create a watermark with ImageMagick however, the guides on layering are pretty daunting.  Basically I'll have one base image say "base.jgp" and an overlay image say "overlay.jpg".  Overlay.jpg would be smaller than base.jpg. Which exec command would I run to place overlay centered on top of base.jpg?</p>
  
  <p>Thanks!</p>