This simple batch script compresses PNG and JPEG files with TinyPNG API https://tinypng.com. It depends on jq tool https://stedolan.github.io/jq/.

tinypng

# Usage:
#   ./tinypng <path> <path> ...
#
# Upload the files to shrink and then save them locally under the same name.
# Only works with JPEG and PNG. Accepts wildcard path for batch compression.
#
# Uses TinyPNG API: https://tinypng.com/developers/reference.
# Uses TINYPNG_API_KEY environment variable for TinyPNG API key.
# Depends on jq: https://stedolan.github.io/jq/

set -euo pipefail

API_KEY=$TINYPNG_API_KEY
API_URL=https://api.tinypng.com/shrink
EMOJIS=("🔥" "⭐️" "❤️" "💯" "👌" "🐝" "💩")

for file in $@ ; do
  emoji=${EMOJIS[$RANDOM % ${#EMOJIS[@]} ]}
  url=$(curl -sf --user "api:$API_KEY" --data-binary @$file $API_URL | jq -r '.output.url')
  curl -sf -o "$file" "$url"
  echo "$emoji  optimized $file"
done