photocrop -- An SDL-based program for efficiently cropping and 
thumbnailing images from digital cameras.  Written by Tyler Montbriand 
in Dec 2005.

I found it inefficient to load each and every image into GIMP, crop it, 
then resize and resave it(TWICE for each image!) so I built a tool to 
automate the process.  It loads, resizes, and crops much faster than The 
GIMP.

It saves JPEGs, and can load any image format supported by SDL_Image.  
It uses libSDL, libSDL_image, and libjpeg.

Here is how you run it:

 photocrop [-X window width] [-Y window height] 
  [-W scaled width] [-H scaled height] 
  [-w thumb width] [-h thumb height] 
  [-o outputdir] 
   image1.jpg [image2.png] [...]

 -X and -Y specify the maximum window width and height, which 
 defaults to 800x600.

 -W and -H specify the maximum output image width and height, 
 which defaults to 800x600.

 -w and -h specify the maximum thumbnail width and height, which 
 defaults to 150x112.

 -o specifies where the resized and thumbnailed images go, the 
 resized ones named [original-filename]n.jpg and the thumbnails 
 named [original-filename]-thumb.jpg respectively.

When you run it, a window will pop open displaying an image and a crop 
box.  The left mouse button positions the top left corner of the crop 
box, and the right mouse button positions the lower right corner of the 
crop box.  Ctrl-enter saves the selected area as resized image and 
thumbnail, pageup/pagedown keys navigate images, and arrow keys are used 
for fine-tuning the crop box.  Here are the keyboard shortcuts in 
detail:
 Keypad + Zero in on selected area
 Keypad - Zoom out to previous selected area
 Keypad * Select whole visible area
 Page Down Switch to next image
 Page Up  Switch to previous image
 Home  Select first image
 End  Select last image
 Left  Move the left border of crop-box left
 Right  Move the left border of crop-box right
 Up  Move the top border of crop-box up
 Down  Move the top border of crop-box down
 Ctrl-right Make the crop-box a little wider
 Ctrl-left Make the crop-box a little narrower
 Ctrl-up  Move the bottom border of crop-box up
 Ctrl-down Move the bottom border of crop-box down 
 Ctrl-Enter Save cropped section and thumbnail, show next