find-malformed-pngs

if [ "$#" -eq 0 ] ; then
  # no arguments, recurse through all folders
  find -regex '[^!]*' -type d -exec bash -c 'shopt -s nullglob; cd "{}" && pwd; for i in *.png; do pngcheck -q "$i" || { head -c 10 -z "$i" && echo && echo ; }; done' \; #we want to see a certain amount of bytes to determine if we're looking at a jpeg instead... this seems pretty good
else
  for i in "$@"; do
     pngcheck -q "$i" || { head -c 10 -z "$i" && echo && echo ; };
  done
fi