Compress png to jpeg by reducing size to limit

gistfile1.txt

#!/bin/bash

if [ -z "$1" ]; then
  echo "Usage: $0 <input_file.png>"
  exit 1
fi

input_file="$1"
filename=$(basename -- "$input_file")
name="${filename%.*}"
target_size=100000   # в байтах
quality=2

while true; do
  ffmpeg -y -i "$input_file" -q:v $quality temp.jpg
  actual_size=$(stat -c %s temp.jpg)
  if [ "$actual_size" -le "$target_size" ] || [ "$quality" -ge 30 ]; then
    mv temp.jpg "$name.jpg"
    break
  fi
  quality=$((quality + 1))
done