PHP image output garbled, how to solve

PHP Image Output garbled
Just started to learn PHP, why this code output garbled
$im = Imagecreate (200,60);
$white = Imagecolorallocate ($im, 225, 66, 159);
Imagegif ($im);
?>


------Solution--------------------
Put a look.
------Solution--------------------

$im = Imagecreate (200,60);
$white = Imagecolorallocate ($im, 225, 66, 159);
   Output image to Browser
Header (' content-type:image/gif ');
Imagegif ($im);

------Solution--------------------
Get rid of the first ------solution--------------------
References:

Quote: References:

You just run the code I gave you is sure Yes

Yes, 3Q. What's that header, the book hasn't been introduced yet?

The header () function sends the original HTTP header to the client.
It is important to recognize that the header () function must be called before any actual output is sent to the browser.
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