Image Compression tools via command line

Question

I'm searching best tool to compress images (png and jpeg) via command line.
After googling I found trimage which is good as it compresses both png and jepeg, but compression ratio is very poor in this case.

I came across jpeg-optimizer.com online tool which does the job way better than trimage. Can any one help to find the right tool for this.

Answer 1

I'm using the following tools to perform lossless image compression:

• pngcrush
• gifsicle
• jpegtran

For each of the programs, I've created two shortcuts:

1. One that does the actual compression, and shows the file size of both files
2. One that replaces the original file with the compressed one (If I'm satisfied, I'll do arrow-up, prefix my previous command with a "m", and press enter).

I've put this in my .bashrc:

# Image optimization tools
png() {
    pngcrush -brute "$1"{,.} && du -b "$1"{,.}
}
gif() {
    gifsicle -O "$1" -o "$1." && du -b "$1"{,.}
}
jpeg() {
    jpegtran "$1" > "$1." && du -b "$1"{,.}
}
# Just for easy access in history
mpng() {
    mv "$1"{.,}
}
mgif() {
    newsize=$(wc -c <"$1.")
    oldsize=$(wc -c <"$1")
    if [ $oldsize -gt $newsize ] ; then
        mv "$1"{.,}
    else
        rm "$1."
    fi  
}
mjpeg() {
    mv "$1"{.,}
}

Note: pngcrush -brute is very verbose. Redirect the output to /dev/null if you're not interested in the progress.