Compress and convert images

README.me

# Convert images from folder

## Installation

You need to download libwebp and put in the shell script folder.
You must have installed the jpegoptim, giflossy (gifsicle), pngquant and imagemagick library.

## Usage

Convert folder and put results in the results folder
./convert.sh -p /path/to/folder 

To overwrite the results folder, use this command
./convert.sh -p /path/to/folder -d /path/to/results

To change the default values of qualities:
./convert.sh -p /path/to/folder -q 70 -q 90 -q 100

Options:
-p images path (current path by default)
-d destination path (results folder by default)
-g enable gif conversion/optimization (optional, disabled by default)
-t name the temporary folder (.temp-folder by default)
-q use this parameter to change the quality of optimization/conversion (30, 50, 60, 70, 80, 100 by default)

Next steps:
* Identify the type of an image and fix the extension
* Use the type of an image as rule to the conditions, not the extension

convert-images.sh

#!/bin/bash

# Defining time to calculate execution
start_time=`date +%s`

# Enabling extglob option to filter file extensions
shopt -s extglob

# Exit if a command exits with a non-zero status
set -e

# Gif conversion/optimization disabled by default
gif_enabled=0

# Path to get images by default
image_path=.

# Temporary folder name, dot to hide the folder
temp_folder=.temp-folder

# Quality list to convert the images
qualities=()

destination_folder=""

# Get flag options
while getopts ":q:p:d:t:g" opt; do
  case $opt in

    # Set the qualities of files
    q) qualities+=("$OPTARG") ;;

    # Set the folder to scan
    p) image_path="${OPTARG%/}" ;;

    # Set the destination of the converted images
    d) destination_folder="${OPTARG%/}" ;;

    # Turn GIF conversion on
    t) temp_folder="${OPTARG///}" ;;

    # Turn GIF conversion on
    g) gif_enabled=1 ;;

    # Stop execution when an invalid option is called
    \?) echo "Invalid option: -$OPTARG" >&2; exit 1; ;;

    # Stop execution when an empty option is called
    :) echo "Option -$OPTARG requires an argument." >&2; exit 1; ;;

  esac
done

# Defining default values to the qualities
if [ -z "$qualities" ]; then
  qualities=( 30 50 60 70 80 90 )
fi;

# If image_path is empty, lets ask the path
if [ -z "$image_path" ]; then
  echo "Warning: Path parameter is missing, you must specify the folder to convert the images"
  exit 1
fi;

# Defining the destination folder default value
if [ -z "$destination_folder" ]; then
  destination_folder="${image_path}/results"
fi;

# Create the destination folder inside the path
mkdir -p ${destination_folder}

# Create a hidden temporary folder
mkdir -p ${image_path}/${temp_folder}

# If gif conversion/optimization is enabled, let's add them
if [ "$gif_enabled" -eq 1 ]; then
  FILES=${image_path}/*.@(jpg|jpeg|png|gif)
else
  FILES=${image_path}/*.@(jpg|jpeg|png)
fi;

# Check the number of files
number_of_files="$(find $FILES 2>/dev/null | wc -l)"

# If there's no files, exit the script
if [ ${number_of_files} -eq 0 ]; then
  echo "There's no image in this folder"
  exit 1;
fi;

# Loop to look every image with the extensions below 
for f in ${FILES}; do
  echo "File $f:";

  # Defining the basename
  base_name=$(basename "$f")  

  # Getting the name of the file without extension
  name=${base_name%.*}

  # Getting the file extension
  extension=${base_name##*.}

  # For every quality, lets convert images
  for i in "${qualities[@]}"; do

    # Optimize the JPG and JPEG
    if [ "$extension" = "jpg" ] || [ "$extension" = "jpeg" ]; then
      echo -e "\tOptimizing JPG/JPEG to $i quality"

      # Define a name to a temporary file
      temp_jpg_filename=${image_path}/${temp_folder}/${name}-q${i}.${extension}

      # Copy the original file and create it with the temporary name
      cp ${image_path}/${name}.${extension} ${temp_jpg_filename}

      # Optimize the image and put in the destination folder
      jpegoptim -o -q -m $i -d ${destination_folder} ${temp_jpg_filename}

      # Remove the temporary file
      rm ${temp_jpg_filename}
    fi;

    # Optimize static PNG files
    if [ "$extension" = "png" ]; then
      echo -e "\tOptimizing PNG with $i quality"
      pngquant --speed 1 --quality ${i}-${i} -f -o ${destination_folder}/${name}-q${i}.png ${image_path}/${name}.${extension}

      # Checking if there's transparency to the image
      opaque=`convert ${image_path}/${name}.${extension} -format "%[opaque]" info:`
      if [ "$opaque" = true ]; then
        echo -e "\tConverting PNG to JPG, because there's no transparency"

        # Convert the PNG to JPG
        convert ${image_path}/${name}.${extension} ${destination_folder}/${name}-q${i}_from_png.jpg

        echo -e "\tOptimizing JPG converted from PNG"

        # Define a name to a temporary file
        temp_jpg_filename=${image_path}/${temp_folder}/${name}-q${i}_from_png_optimized.jpg

        # Copy the original file and create it with the temporary name
        cp ${destination_folder}/${name}-q${i}_from_png.jpg ${temp_jpg_filename}

        # Optimizing the JPG
        jpegoptim -o -q -m $i -d ${destination_folder} ${temp_jpg_filename}

        # Remove the temporary file
        rm ${temp_jpg_filename} 
      fi;
    fi;

    # Convert static images to WEBP
    if [ "$extension" = "jpg" ] || [ "$extension" = "jpeg" ] || [ "$extension" = "png" ]; then
      echo -e "\tConverting to WEBP with $i quality"
      ./libwebp/bin/cwebp -quiet -m 6 -q $i ${image_path}/${name}.${extension} -o ${destination_folder}/${name}-q${i}.webp
    fi;

    # Convert gif/animated gif to WEBP
    if [ "$extension" = "gif" ]; then
      echo -e "\tConverting to WEBP with $i quality"
      ./libwebp/bin/gif2webp -quiet -lossy -q $i -m 6 ${image_path}/${name}.${extension} -o ${destination_folder}/${name}-q${i}.webp
    fi;

  done;

  # Optimize GIF images/animations
  if [ "$extension" = "gif" ]; then
    echo -e "\tOptimizing GIF with lossy compression and 64 colors"
    gifsicle -O3 --colors=64 --lossy=100 ${image_path}/${name}.${extension} -o ${destination_folder}/${name}-q64.gif

    echo -e "\tOptimizing GIF with lossy compression and 125 colors"
    gifsicle -O3 --colors=128 --lossy=100 ${image_path}/${name}.${extension} -o ${destination_folder}/${name}-q128.gif

    echo -e "\tOptimizing GIF with lossy compression and 256 colors"
    gifsicle -O3 --colors=256 --lossy=100 ${image_path}/${name}.${extension} -o ${destination_folder}/${name}-q256.gif
  fi;

  echo ""
done;

# Remove the hidden temporary folder
rm -rf ${image_path}/${temp_folder}

# Defining the end time for the execution calculation
end_time=`date +%s`

echo "Script finished in $((end_time-start_time)) seconds"