This question has already been answered:
I started learning PHP the other day and can't understand the error. When i write code
header("Content-type: image/jpeg"); // и вообще пытаюсь послать любой заголовок
PHP says:
Warning: Cannot modify header information - headers already sent by
// my script on the first line
Tell me, who sends headers (Apatch php or who)? And how do I completely control the output or disable the automatic sending of headers?