Resize images (shrink only) to screen sized .jpg

bash-resize.sh

#!/bin/bash
#
# Resize images (shrink only) to screen sized .jpg
#
# (c) 2015 Bernd Busse
#

BLUE="\e[1;34m"
RED="\e[1;31m"
GREEN="\e[1;32m"
RESET="\e[0m"


echo " === Image Resize and Convert === "

folders=
f_len=0
f_ctr=0

_PWD="$( pwd )"

# filter arguments
while [[ -n ${1} ]]; do
    if [[ -d "${1}" ]]; then
        folders="${folders}${folders:+\n}${1}"
    fi
    shift
done
f_len=$( echo -e "${folders}" | wc -l )

# go to given directories
while read -r d; do
    f_ctr=$(( ${f_ctr} + 1 ))
    echo -e "${BLUE}::${GREEN} entering \"${d}\" (${f_ctr}/${f_len})${RESET}"
    cd "${d}"
    if (( ${?} != 0 )); then
        exit 10
    fi
    
    ctr=0
    for f in ./*; do
        ctr=$(( ${ctr} + 1 ))

        info="$( identify -format '%w:%h:%e' "${f}" 2> /dev/null)"
        if (( ${?} != 0 )); then
            # not a compatible image file
            continue
        fi

        width=$( echo "${info}" | cut -d ':' -f 1 )
        height=$( echo "${info}" | cut -d ':' -f 2 )
        ftype="$( echo "${info}" | cut -d ':' -f 3 )"
        if (( ${width} > 1920 )) || (( ${height} > 1200 )) || [[ ${ftype} != "jpg" ]]; then
            # convert image
            echo -e "  ${BLUE}::${GREEN} converting \"${f}\"${RESET}"
            convert "${f}" -resize 1920x1200\> "${f%.*}.jpg"

            if [[ ${ftype} != "jpg" ]]; then
                # delete old file
                echo -e "    ${BLUE}::${RED} delete \"${f}\"${RESET}"
                rm "${f}"
            fi
        fi

        # progress output
        if (( (${ctr} % 100) == 0 )); then
            echo -e "  ${BLUE}[PROGRESS]${GREEN} Checked ${ctr} files${RESET}"
        fi
    done

    echo -e "${BLUE}::${GREEN} leaving \"${d}\"${RESET}"
    cd "${_PWD}"

done < <( echo -e "${folders}" )