A little searching around yielded some interesting projects...
This may help you/those who need customized PDFs'
FROM the Developer of PAPERCROP
1. How can I change output resolutions?
Open config.lua and edit "device_width=600", "device_height=800" appropriately.
2. How can I change output format?
Edit config.lua. Find ".gif" and replace it as .jpg, .bmp or .png.
3. How can I improve readability?
Edit config.lua. One can adjust image processing parameters such as sharpen, contrast, gamma, dithering, and color depth.