How to remove parent's image size from child theme?

In the functions.php

line 33-37 of the parent’s function.php outside a function, no hooks

if ( function_exists( 'add_image_size' ) ) {
	add_image_size( 'full-size',  9999, 9999, false );
	add_image_size( 'nivo-slider',  980, 400, true );
	add_image_size( 'post-image',  660, 220, true );
	add_image_size( 'portfolio-thumb',  290, 190, true );
	add_image_size( 'portfolio-single',  500, 9999, false );

Didn’t help, in my case.

The codes are placed outside a function.

The parent theme is Proyecto. I’ve put the download link below:

Proyecto by AJ Clarke from WPExplorer.com
[ Redacted, please do not post links to themes like that use the author’s link instead http://www.wpexplorer.com/proyecto-free-business-portfolio-wordpress-theme ]

No it doesn’t.

What should I do?

Thanks

Thanks wahmaholic, it worked out perfectly!