batch_crop left top width height image1 image2 ...
DESCRIPTION
The area defined by the rectangle left, top, width, height is cropped out of
each of the images and saved in a file of the same name, but prefixed by
"crop_".
For example:
batch_crop 10 10 100 100 fred.jpg jim.png
will make two images, crop_fred.jpg and crop_jim.png, each of 100 by 100
pixels, taken from the corresponding input images.
