帮我看看这个错误提示是啥么意思啊?
<br />
<b>Fatal error</b>: Call to undefined function: imagecreate() in <b>D:\my work\stampcenter\3.php</b> on line <b>3</b><br />
PHP的内容是:
<?php
Header("Content-type: image/gif");
$im = imagecreate(400,30);
$black = ImageColorAllocate($im, 0,0,0);
$white = ImageColorAllocate($im, 255,255,255);
ImageTTFText($im, 20, 0, 10, 20, $white, "c;\windows\fonts\arial.ttf", "I am NUMBER ONE !!");
ImageGif($im);
ImageDestroy($im);
?>