I am guessing this plugin does not work with ImageMagick. Since the default image processor in WordPress strips all the metadata from the images I upload I prefer using ImageMagick. I saw a posting that said it didn't work but then was updated to that it did.
Actually I deactivated ImageMagick and it still doesn't work. Maybe another problem altogether.
In media library I select crop image a grayed out image appears in pop up but I can do nothing.