How Recursively Compress Png Images
| find . -type f -name ‘*.png’ | xargs pngcrush -brute_force –extraneous |
| ls *.png | while read line; do pngcrush -brute $line compressed/$line; done |
This is the best one:
find . -iname ‘*png’ -exec pngcrush -ow -brute {} {}.crush \;