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filter is not described

upload_size_limit filter-hook . WP 2.5.0

Filters the maximum upload size allowed in php.ini.


add_filter( 'upload_size_limit', 'filter_function_name_5859', 10, 3 );
function filter_function_name_5859( $size, $u_bytes, $p_bytes ){
	// filter...

	return $size;
Max upload size limit in bytes.
Maximum upload filesize in bytes.
Maximum size of POST data in bytes.

Where the hook is called

wp-includes/media.php 2998
return apply_filters( 'upload_size_limit', min( $u_bytes, $p_bytes ), $u_bytes, $p_bytes );

Where the hook is used (in WP core)

wp-includes/ms-default-filters.php 98
add_filter( 'upload_size_limit', 'upload_size_limit_filter' );