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filter is not described

fallback_intermediate_image_sizes filter-hook . WP 4.7.0

Filters the image sizes generated for non-image mime types.

Usage

add_filter( 'fallback_intermediate_image_sizes', 'filter_function_name_989', 10, 2 );
function filter_function_name_989( $fallback_sizes, $metadata ){
	// filter...

	return $fallback_sizes;
}
$fallback_sizes(array)
An array of image size names.
$metadata(array)
Current attachment metadata.

Where the hook is called

wp_generate_attachment_metadata()
fallback_intermediate_image_sizes
wp-admin/includes/image.php 222
$fallback_sizes = apply_filters( 'fallback_intermediate_image_sizes', $fallback_sizes, $metadata );

Where the hook is used (in WP core)

Does not used.