Linux Shell Scripting Cookbook - Third Edition

How to do it...

The convert program will convert a file from one image format to another:

    $ convert INPUT_FILE OUTPUT_FILE

Here's an example of this:

    $ convert file1.jpg file1.png

We can resize an image by specifying the scale percentage or the width and height of the output image. To resize an image by specifying WIDTH or HEIGHT, use this:

    $ convert imageOrig.png -resize WIDTHxHEIGHT imageResized.png

Here's an example of this:

    $ convert photo.png -resize 1024x768 wallpaper.png

If either WIDTH or HEIGHT is missing, then whatever is missing will be automatically calculated to preserve the image aspect ratio:

    $ convert image.png -resize WIDTHx image.png

Here's an example of this:

    $ convert image.png -resize 1024x image.png

To resize ...