max-upload-size.php

<?php
/**
 * Filter the upload size limit for non-administrators.
 *
 * @param string $size Upload size limit (in bytes).
 * @return int (maybe) Filtered size limit.
 */
function filter_site_upload_size_limit( $size ) { 
    $size = 60 * 1024 * 1024; 
    return $size;
}
add_filter( 'upload_size_limit', 'filter_site_upload_size_limit', 20 );

Add this to your functions.php file to increase the max file upload size