Get random image from Joomla directory

gistfile1.php

/**
 * Returns a random image from /image/homeslides/
 *
 * @return mixed
 */
function randomImage()
{
	// Use full system path for security
    $files = glob(JPATH_BASE . '/images/homeslides/*.jpg');
    // Get random image
    $index = array_rand($files);
    // Return path relative to base of site, not full system path
    return str_replace(JPATH_BASE, JURI::base(true), $files[$index]);
}