Compress and convert images

README.md

Convert images to webp 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"