Issue with displaying image png with php -

i have issue displaying image stored on debian server outside path accessible webserver in order keep safe. here's link expected results, relevant php code below:

header("content-type: image/png"); if (isset($_post['mot_de_passe']) , $_post['mot_de_passe'] ==  "superpassword") {     // if password valid     $filename = "/home/image/test.png";     $handle = fopen($filename, "rb");     $contents = fread($handle, filesize($filename));     fclose($handle);     echo $contents; } else {     // if password invalid     echo '<p>mot de passe incorrect</p>'; } 

this below statement should first line of script. means before html output. solves issue

 header("content-type: image/png");