Hi,
I have created some image processing routines and an interface for them. I call it Pip (for Powershot image processor). The routines work on the viewport (LCD) image and don't apply to the .jpg files on the camera.
You can do an auto image enhancement, brightness and contrast changes, hue shifts, saturation changes, determine the mean and Standard deviation in a region of interest, create edge images, do unsharp masking, invert the brightness, etc.
There are 10 disk buffers available for viewport saving and loading.
Because it only works on the viewport it is of limited usefullness. I am putting these files here in the hope that someone will find it of interest and maybe make some improvements.
For more information see the help file PipHelp.txt.
I have only tested this on my A720 and A570.
The zip file holds the sources of files that I changed. The build I used was 609.