Resizing Images

To recursivly resize images over 2000px width while preserving teh images aspect ratio and  ignoring smaller images

find . -iname "*.jpg" -exec convert "{}" -resize '2000>' "{}" \;

you can add -quality 90 to further reduce the size

To recursivly crop an image

for file in ./*.jpg; do convert "$file" -gravity Center -shave 20x20 "./out/${file%.JPG}"; done;