How To Change Default Thumbnail Sizes In Extra

functions.php

function custom_extra_add_image_sizes() {
	$sizes = array(
		'extra-image-huge'          => array(
			'width'  => 1280,
			'height' => 720,
			'crop'   => true,
		),
		'extra-image-single-post'   => array(
			'width'  => 1280,
			'height' => 640,
			'crop'   => true,
		),
		'extra-image-medium'        => array(
			'width'  => 627,
			'height' => 353,
			'crop'   => true,
		),
		'extra-image-small'         => array(
			'width'  => 440,
			'height' => 247,
			'crop'   => true,
		),
		'extra-image-square-medium' => array(
			'width'  => 440,
			'height' => 440,
			'crop'   => true,
		),
		'extra-image-square-small'  => array(
			'width'  => 150,
			'height' => 150,
			'crop'   => true,
		),
	);

	foreach ( $sizes as $name => $size_info ) {
		add_image_size( $name, $size_info['width'], $size_info['height'], $size_info['crop'] );
	}
}
remove_action('after_setup_theme', 'extra_add_image_sizes',10);
add_action( 'after_setup_theme', 'custom_extra_add_image_sizes',20 );

Text

All Extra thumbnails sizes are listed in one file: core.php. It's possible to redefine all of them or just few by adding the following code into functions.php file in child theme:

In the array above you can see the sizes for different pages/modules. Just modify what you need. That's it.

I'd suggest connecting to your site via FTP to make these changes, it will be easier to rollback the changes if you make a syntax error. It is better to use a child theme to make PHP changes. I attached the child theme file at the end of my message.

Let me know how it goes. 😃