Browsing it on Firefox 30.0 at 1280x1024 and all the pictures look to be badly resized:

http://i.imgur.com/C7QptVL.png

This does not happen in Chrome 35.0 or, funnily enough, IE11.

EDIT: Playing around in Inspector, it's directly related to this CSS attribute on the images:

  image-rendering: -moz-crisp-edges;

EDIT2: I'm also getting weird word wrapping, which you can also see in the above image. It's breaking on "you've" and "idea". Directly related to:

  word-break: break-all;