Script for compressing images. Saves me about 25-30% of space with no visible difference. Measured on pictures from my 10MP camera.

compress_image.sh

#!/bin/bash

# Script for compressing images. Saves me about 17% of space with no visible
# difference. Measured on > 250 pictures from my 10MP camera.

for image in "$@"
do
  # Make exif tag in jpg - set's the file's creation date.
  jhead -mkexif $image
  convert -resize 80% -quality 85 $image $image
  # Convert touched the file, tainting the creation date. Set it from the exif
  # tag.
  jhead -ft $image
done