Batch resize png images with bash and ImageMagick

batch-convert.sh

#!/bin/sh

convert_path="C:/Program Files/ImageMagick/convert.exe"
target_path="."
target_ext="png"

echo "Warning, this will overwrite the current images."

read -r -p "Do you want to continue? [y/N] " response
response=${response,,}  # tolower
if [[ $response =~ ^(yes|y)$ ]]
then
    for f in ${target_path}/*.${target_ext};
    do
        echo "Resizing ${f}..."
        "$convert_path" "$f" -resize 20% "$f"
    done
else
    echo "Exiting..."
fi