How to easily resize images via command-line?

Question

I would like to know how to resize images in Ubuntu. What is the easiest tool to do so?

Answer 1

First, install ImageMagick via:

sudo apt-get install imagemagick

Then, open a terminal and run this command:

convert -resize 20% source.png dest.jpg

It will reduce the size to 20%, not by 20%.
The resulting image will be much smaller, 20% of the former size, and not 20% smaller than before.

You can also specify the size in pixels:

convert -resize 1024X768 source.png dest.jpg

You can also use: mogrify command-line tool from the same package.

Answer 2

nautilus-image-converter is a nautilus extension to mass resize or rotate images. To install nautilus-image-converter in all currently supported versions of Ubuntu open the terminal and type:

sudo apt install nautilus-image-converter

It adds two context menu items in nautlius so you can right-click and choose "Resize Image". (The other is "Rotate Image").

You can do a whole directory of images in one go if you like and you don't even have to open up an application to do so.

You need to restart your nautilus to see new context menus, run nautilus -q and then click the Home folder icon to reload nautilus with the new plug-in.

Answer 3

sudo apt-get install imagemagick

The command mogrify overwrites the original files with the resized images:

mogrify -resize 50% *.png      # keep image aspect ratio
mogrify -resize 320x240 *.png  # keep image aspect ratio
mogrify -resize 320x240! *.png # don't keep image aspect ratio
mogrify -resize x240 *.png     # don't keep image aspect ratio
mogrify -resize 320x *.png     # don't keep image aspect ratio

^{Note: You can add -auto-orient to automatically orient converted images.}

Answer 4

If you're just doing a couple of images, most image editors in Ubuntu (Gimp, F-Spot, etc) will let you do a basic resize.

If you want to edit tens, hundreds or thousands of images, I prefer Phatch. Phatch is a GUI-based batch photo editor that will let you perform a whole load of transformations on images. sudo apt-get install phatch

ImageMagick is good but it's a bit tedious if you don't know the setting names for things. You can very quickly learn Phatch by clicking around.

Answer 5

ImageMagick is the package you want. It contains a number of useful command line tools for this very purpose.

Here's a simple tutorial explaining how to batch resize images:-

mogrify -resize 320x240 *.jpg

After this command is completed, all of the images will be replaced with resized version of themselves. Notice that in an effort to preserve the image aspect ratio, mogrify may not be produce images that are exactly 320x240. To force this to happen, modify the original command to by placing an exclamation point at the end of the desired resolution:

mogrify -resize 320x240! *.jpg

Answer 6

No need to install any new software just do this

convert -resize 50% myfigure.png myfigure.jpg

or

convert myfigure.png -resize 200x100 myfigure.jpg

Answer 7

At the moment nautilus-image-converter does not work in Ubuntu 13.10. Therefore I use imagemagick on the command line, which is very good workaround (at least for me).

sudo apt-get install imagemagick

Keep in mind the difference between these imagemagick tools:

• Mogrify does processing on the same image, it reads file modify file and writes the output to the same file.
• Convert is meant to work on separate images, reads file and modify and write to different file/format. You can also use convert command to use output file same as input file.

I often use mogrify to simply resize multiple images and overwrite the original files. I. e. this command would scale down the dimension of all JPG files to 40% of the original dimension:

mogrify -verbose -resize '40%' *.JPG

Answer 8

GIMP is probably the easiest way, since it has a fairly simple UI for such common tasks. All you have to do is open up your image and go to Image → Image Size and then change accordingly. There are ways to do batch resizing using the GIMP as well, but I don't know them by heart.

Answer 9

Install gthumb. Simple and easy for basic image handling and editing functions - viewer, resizing, cropping, rotate, flip, grayscale, etc with options to save in JPEG, PNG, TIFF, TGA formats.

To install gthumb:

• Open your terminal
• Type sudo apt-get install gthumb
• Accept the changes

Answer 10

You can also use the ubiquitous ffmpeg (or avconv) tool to resize images:

ffmpeg -i image.jpg -s 4096x2048 image-resized.jpg

And if you want really fast JPEG image resizing - try epeg (as mentioned here and there) - which needs to be built from source.

Answer 11

There is a good multiplatform tool called XnConvert. Combine and choose between more than 80 different operations. The installation is simple through deb. file from the official website.

It is free but not opensource, perhaps that's just the beauty of it.

Answer 12

For GUI, Phatch "one click is worth thousand photos" is the best for such quick job. It is already in Ubuntu repository. It has plenty of actions and options as imagemagick.

sudo apt-get install phatch

Update:

Phatch project is DISCONTINUED unfortunately, last code commit was on 2011-01-24. It is on LP/Launchpad (Frameworks: Python2/PyGTK2.8)

Answer 13

open the image in ImageMagick.

1. click on the image command box will be open.
2. view->resize enter the pixel you want. click on resize button.
3. File-> save, enter the name. click on Format button choose the format you want and click select button.
4. click on save button.

another option is select view -> original image and Drag the corners of the image to resize it. select File -> save.

Answer 14

I use Pimagizer. It works great and it is the easiest application I have used. Tested on Ubuntu 14.04, 15.04, 15.10.

sudo add-apt-repository ppa:vfrico/stable
sudo apt-get update
sudo apt-get install pimagizer

See : https://launchpad.net/pimagizer/ for more infos.

Answer 15

The script to resize all .png files in a folder to 30%. The original file can either be removed (if delete_original is true), or stays, in that case the resized file would get a name postfix rename_postfix:

#!/bin/bash

rename_postfix="-small"
delete_original=true
substr=".png"
for str in *.png; do
    #reverse strings
    reverse_str=$(echo $str | rev)
    reverse_substr=$(echo $substr | rev)
    
    #find index of reversed substring in reversed string
    prefix=${reverse_str%%$reverse_substr*}
    reverse_index=${#prefix}
    
    #calculate last index
    index=$(( ${#str} - ${#substr} - $reverse_index ))
    
    # Extract the filename without extension
    filename="${str:0:index}"
    if $delete_original; then
        # the name can remain, because the original will be removed
        new_filename="${str}"
    else
        # need a new name, two files will remain
        new_filename="${filename}${rename_postfix}${substr}"
    fi

    echo "extension = ${substr}, original = ${str}, filename = ${filename}, new = ${new_filename}"
    
    # Resize and convert the file to .jpg
    convert -resize 30% "${str}" "${new_filename}"
done