This is a copy of Greg Lavino's awesome photo_splitter.py, with some minor adjustments by myself.
Greg published his original code in a ubunutuforums.org thread.
photo_splitter.py is very useful if you need to crop a large amount of images very quickly. Simply select the areas in the image that you want to crop, click "Go" and photo_splitter will create one image file for each crop area for you, in the same folder as the original image.
Here's a screenshot from the StackOverflow question which features photo_splitter.py as the solution:
CropperTktoPDF
Before you can run photo_splitter.py, you'll need to install these libraries:
sudo apt-get install python-tk python-imaging python-imaging-tk python-reportlab
An example:
./croppertk.py dog.jpg
or:
./croppertk.py
Make a for loop to process a bunch of images:
for img in ~/images/*; do ./croppertk.py $img; done