Image compression from the command line
development
ID: 20170720
ACCESSING DATA...
SYSTEM: ARCHIVE
FILE: IMAGE COMPRESSION FROM THE COMMAND LINE
STATUS: ACTIVE
Here’s a small script to compress JPEG images in a folder. Useful to save a few kilobytes of bandwith when serving images from your website.
I might improve this script in the future to include more compression tools and/or file extensions.
#!/bin/bash
for f in *.jpg *.JPG *.jpeg *.JPEG
do
echo -en "Converting ${f} ... "
kb_orig=`du -k "${f}" | cut -f1`
convert -quality 70 ${f} ${f}
kb_after=`du -k "${f}" | cut -f1`
pct_gain=`expr ${kb_after} \* 100 / ${kb_after}`
echo " (${kb_orig}kb ==> ${kb_after}kb) DONE - ${pct_gain}%."
done
To generate highly compressed thumbnails.
#!/bin/bash
# Thumbnail generator
MEDIA_DIR="/path"
cd ${MEDIA_DIR}
# CONVERT
for f in ${MEDIA_DIR}/*
do
complete_filename=$(basename "$f")
extension="${f##*.}"
full_filename="${f%.*}"
#echo $complete_filename $full_filename $extension
echo -ne "Converting ${complete_filename} ... "
kb_orig=`du -k "${f}" | cut -f1`
convert -define peg:size=500x500 ${f} \
-auto-orient -thumbnail 500x500 -unsharp 0x.5 ${full_filename}_thumb.gif
kb_after=`du -k "${full_filename}_thumb.gif" | cut -f1`
pct_gain=`expr 100 - ${kb_after} \* 100 / ${kb_orig}`
echo -e "(${kb_orig}kb ==> ${kb_after}kb) \033[96m${pct_gain}\033[39m%."
done