Featured Image meta box manipulation plugin

A small utility plugin to manipulate the built-in Featured Image meta box.

The problem

Sometimes the Featured Image is just the perfect meta box for the job save for its generic name: that might not be the best in any occasion.
Say I've registered a custom post type to model books then "Featured image" is less clear and precise than "Cover picture".
Filters exist to solve the issue but I keep forgetting that the meta box has an Ajax-powered side that will eschew changes when removing an existing image or adding a new one; initial state of the post edit screen will be fine but the first Ajax call will restore the default link labels.

An amazing english solution

The Extended CPTs plugin will take care of replacing the featured image labels using a slick and painless interface. If the site is in english.
Much of my job is not in english though and I've made something I could use to modify the featured image link labels and titles with as little code as possible but leaving open my internationalization possibilities.

Another solution

I've pushed a working version of a plugin doing just that to GitHub and allows for a little more customization including context and priority settings.