How do I control the compression rate of mogrify?

Question

I want to do something like

mogrify -format jpg *.png

However, I want to encode the jpg at a higher quality than the default. Is there a way to do this?

Answer 1

mogrify -format jpg -quality 100 *.png

According to the official documentation the quality parameter can be 1 - 100 and the effect varies depending on the resulting format.

• For JPG output a value of 1 gives worst quality and highest compression; a value of 100 gives best quality and lowest compression.
• For PNG files the quality parameter only changes the lossless compression strategies used, so the speed of compression and the resulting file size can be affected but image quality remains the same.

With any Linux command, you can enter

man [command]

To see the help page that list out the information and parameters available.