Grid Cropped

Grid Fixed Width Covers

Grid Fixed Height Covers

They also generate newsletter images:
Cropped Example
http://ltfl.librarything.com/forlibraries/images/bdw/5506/26378/latest.png

Fixed Height:
http://ltfl.librarything.com/forlibraries/images/bdw/5506/26380/latest.png

Fixed Width:
http://ltfl.librarything.com/forlibraries/images/bdw/5506/26379/latest.png