How to Disable Image Compression in WordPress

Hi

How to Disable Image Compression in WordPress

If I’m adding the following code to my theme’s functions.php file.
Does it go in the Generate Press Child theme?

add_filter('jpeg_quality', function($arg){return 100;});

From tutorial here:
https://www.wpbeginner.com/wp-tutorials/how-to-increase-or-decrease-wordpress-jpeg-image-compression/

Thanks
Scott