This is what it looks like when the plugin is activated.
Here is the plugin on a more populated blog. Notice that the images are transparent and Chris Hopf's avatar is consistent with his entries even though that avatar is randomly assigned. Michael Barber has a Gravatar so his was left untouched.
Requires: 3.0 or higher Compatible up to: 3.9.1 Last Updated: 2014-4-24 Downloads: 2,476