This is simple script to save / collect cropped bitmaps.
It finds all bitmaps with crop and save them as new cropped jpgs.
Just open it in Script Editor, change destination folder and file Name prefix and run it.
It's coming with more options as part of Bitmap Tracking/Resizing...
http://www.scriptspot.com/3ds-max/scripts/bitmap-tracking-resizing
Pixamoon