WordPress at a glance
filter is not described

woocommerce_gallery_image_size filter-hook . WC 1.0

Image source.

Usage

add_filter( 'woocommerce_gallery_image_size', 'filter_function_name_3373' );
function filter_function_name_3373( $string ){
	// filter...

	return $string;
}
$string
-

Where the hook is called

wc_get_product_attachment_props()
woocommerce_gallery_image_size
wc_get_gallery_image_html()
woocommerce_gallery_image_size
woocommerce/includes/wc-product-functions.php 789
$image_size      = apply_filters( 'woocommerce_gallery_image_size', 'woocommerce_single' );
woocommerce/includes/wc-template-functions.php 1505
$image_size        = apply_filters( 'woocommerce_gallery_image_size', $flexslider || $main_image ? 'woocommerce_single' : $thumbnail_size );

Where in WP core the hook is used WooCommerce

Usage not found.