How to batch resize and compress images in linux

retro cmaer In this tutorial I will show you how to batch resize and compress images in Ubuntu or in any other Linux distros(debian,arch and fedora).

‘Convert’ command is a very powerful image manipulation utility which comes preinstalled in almost all Linux distributions (ubuntu,debian,arch and fedora) and it is a part of ImageMagick software suite.

Check if convert command is available on your Linux distro

 convert -version


Version: ImageMagick 6.9.7-4 Q16 x86_64 20170114 Copyright: © 1999-2017 ImageMagick Studio LLC

If the above command is not found on your Linux distro you can install it by typing the below command.

Install convert tool on Ubuntu / Debian

 sudo apt-get install imagemagick

Install convert tool on fedora

 sudo dnf install imagemagick

Install convert tool on arch

 sudo pacman -S imagemagick

Note: It’s always good idea take backup of your images before running convert command.

Batch resize and compress images with convert command

Below command will resize and compress all images ending with .jpg extension in a ‘for loop’ and save the compressed/resized image as ‘filename-Optimized.jpg’.

–quality : this option is used to set the image compression level in percentage

-resize : this option is used to resize the image to a given resolution , You can use -resize option with width ( -resize 1600x ) only or both width and height ( -resize 1600×900), In both cases convert command will automatically adjust the given resolution to get optimum aspect ratio so you don’t have to worry about stretched images.

Note: some jpeg image extensions may end with .JPG (in capital letters) ,Since Linux is case-sensitive you may need to adjust the bash script accordingly.

Open terminal and cd into the directory containing your photos and execute below command

 mkdir photos-Optimized;for photos in *.JPG;do convert -verbose "$photos" -quality 85% -resize 1600x900 ./photos-Optimized/"$photos-Optimized.jpg"; done

Voilà! Now you have successfully resized/compressed images, You can see the optimized images in the photos-Optimized directory.

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