function for convert an image into a thumb and displaying it

#******************************************************************************
# function for convert an image into a thumb and displaying it
#******************************************************************************

function create_thumb($filename,$neww,$newh){
header('Content-type: image/jpeg');
list($width, $height) = getimagesize($filename);
$newwidth = $neww;
$newheight = $newh;
$img = imagecreatetruecolor($newwidth, $newheight);
$source = imagecreatefromjpeg($filename);
imagecopyresampled($img, $source, 0, 0, 0, 0, $newheight, $newheight, $width, $height);
imagejpeg($img);
}

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