What is the process you are using to sharpen the images? A feature request would be to add a command line parameters to have some control over the amount the image is sharpened.

I like the program though. It's very simple for me to set something up for a novice PC user to scale their images.

A simple convolution matrix is used for sharpening:

(-2 -2 -2)

(-2 19 -2)

(-2 -2 -2) / 11

I think a new command line only switch wold not hurt anything...