Controle of GIF geanimeerd is of niet

<?php
	function check_animated($filename) {
		$filecontents=file_get_contents($filename);
		if(substr_count($filecontents,"\x00\x21\xF9\x04") > 1) {
			return true;
		} else {
			return false;
		}
	}

	// 2 Voorbeelden
	$file_animated = "file_animated.gif";
	$file_flat = "file_flat.gif";

	if (check_animated($file_animated)) {
		echo $file_animated." is animated <br/>";
	} else {		
		echo $file_animated." is not animated <br/>";
	}

	if (check_animated($file_flat)) {
		echo $file_flat." is animated <br/>";
	} else {		
		echo $file_flat." is not animated <br/>";
	}

<?php
	function check_animated($filename) {
		$filecontents=file_get_contents($filename);
		if(substr_count($filecontents,"\x00\x21\xF9\x04") > 1) {
			return true;
		} else {
			return false;
		}
	}
 
	// 2 Voorbeelden
	$file_animated = "file_animated.gif";
	$file_flat = "file_flat.gif";
 
	if (check_animated($file_animated)) {
		echo $file_animated." is animated <br/>";
	} else {		
		echo $file_animated." is not animated <br/>";
	}
 
	if (check_animated($file_flat)) {
		echo $file_flat." is animated <br/>";
	} else {		
		echo $file_flat." is not animated <br/>";
	}