[Plugin: Max Image Size Control] Does it work with image URLs

I am trying your plugin and I can’t seem to get it to work. I am loading the image through a URL. In Settings>Max Image Size Control, I checked the box to make it apply to all posts, and I put dimensions in each of the sizes. I tried it with crop checked and unchecked. Nothing worked. I’m using Atahualpa 3.5.1 as my theme.

http://wordpress.org/extend/plugins/max-image-size-control/