Invalid title is indicated on the page and namely mime-type!

<?php
$data = array(1, 2, 3, 4, 3, 2, 1);
$im = imagecreate(count($data), 7);
$background = imagecolorallocate($im, 255, 255, 255);
$color = imagecolorallocate($im, 0, 0, 0);
for($i=0; $i<count($data); $i++){
imagesetpixel($im, $i, $data[$i], $color);
}
header("Content-type: image/png");
imagepng($im);
imagedestroy($im);
?>

I’ve typed like this. I start "localhost/****.php" in the browser. First it is starting very long time and then nothing! Blank browser ‘blank page’.

Can someone prove himself if it functions or not?

And here is another thing! In the editor operator imagepng($im) isn’t indicated in bold like the rest – something may be disconnected. Give me a tip what should be switched on.

I’ve forgotten to switch on Apache before starting. But it isn’t working anyway. It has written following stuff:

Warning: Cannot modify header information - headers already sent by (output started at z:\home\localhost\www\graph.php:8) in z:\home\localhost\www\graph.php on line 16
‰PNG   IHDRjuЕђPLTEzzzUВУ~IDATxjc``hbpaР` ` piUf…\IEND®B`‚

What should I do?
Line 16 is a header

At least you are to switch on GD. And you are to check against blank strings at home. It will be a good manner to write mime-type as the first line after <?php

do you use denver? If so delete it immediately and install XAMPP ( http://apachefriends.com/ )

I advise you to pay attention to [ JPGRAPH ] for working with graphics.