Find whether an image is a truecolor image in PHP

<?php/*from  ww w .  j a  v  a  2  s.  c o  m*/
// Create an image instance
$im = imagecreatefromgif('php.gif');

// Check if image is a true color image or not
if(!imageistruecolor($im))
{
    // Create a new true color image instance
    $tc = imagecreatetruecolor(imagesx($im), imagesy($im));

    // Copy over the pixels
    imagecopy($tc, $im, 0, 0, 0, 0, imagesx($im), imagesy($im));
    imagedestroy($im);

    $im = $tc;
    $tc = NULL;

    // OR use imagepalettetotruecolor()
}

// Continue working with image instance
?>