Convert pdf files to png

find -name "*.pdf" -print -exec pdftoppm -r 300 -freetype yes -aa yes -aaVector yes "{}" "{}" \;

find -name "*.ppm" -print -exec convert "{}" -resize 800x600 "{}.png" \;

rm *.ppm

use mmv to change the names


Notes:
- Remove duplicates
- Replace colors