PHP header ('Content-Type: image/png')

Question

I have a problem with header in php.

I havet this simple code.

<?php
header ('Content-Type: image/png');
$im = @imagecreatetruecolor(120, 20)
      or die('Cannot Initialize new GD image stream');
$text_color = imagecolorallocate($im, 233, 14, 91);
imagestring($im, 1, 5, 5,  'A Simple Text String', $text_color);
imagepng($im);
imagedestroy($im);
?>

I think it should works fine, but it didn't. There is no error, and in top-left corner of my browser a little crashed picture icon shows up.

I think header is the problem.

other useful infos: PHP Version 5.3.10-1ubuntu3.9 GD Support enabled GD Version 2.0 FreeType Support enabled FreeType Linkage with freetype FreeType Version 2.4.8

UPDATE In IE even if i have header, i got bunch of data...

Answer 1

For draw image in browser its have to send two headers before the main image data. First it is type of the data

header ('Content-Type: image/png'); 
//or
header ('Content-Type: image/jpeg');

and second it is data length. Without that header browser will be not know where the data ended.

header("Content-length: $size");   //$size image file size in bytes

need check php file have not any spaces and new lines before <?php and no php output before headers and image data output.