Run jpegtran on every image in a directory (and subdirectories)

jpegtran-directory.sh

#!/usr/bin/env bash

function optimize
{
    echo $1
    filesize=`stat -f %z "$1"`
    if [[ $filesize -lt 10000 ]]; then
        jpegtran -copy none -optimize "$1" > "$1.bak"
        echo "pet
    else
        jpegtran -copy none -progressive "$1" > "$1.bak"
        echo "grand"
    fi
    
    if [[ $filesize -lt `stat -f %z "$1.bak"` ]]; then
        echo "compression plus lourde"
        rm "$1.bak"
    else
        echo "good!"
        mv "$1.bak" "$1"
    fi
}
find . -name '*.jpg' -type f -print0 |while read -d $'\0' i; do optimize "$i"; done

You just forgot the ending quote on line 9
And thanks so much for the script