Why image removed after using it One time PHP && TCPDF ?

I am using TCPDF to generate pdf files and i am using image as a background and it works fine for one time after that it removed from the server ?

my code

class MYPDF extends TCPDF {

public function Header() {

    $bMargin = $this->getBreakMargin();

    $auto_page_break = $this->AutoPageBreak;

    $this->SetAutoPageBreak(false, 0);

    $img_file = 'upload/pdf_image.jpeg';

    $this->Image($img_file, 0, 0, 210, 297, '', '', '', false, 300, '', false, false, 0);

    $this->SetAutoPageBreak($auto_page_break, $bMargin);

    $this->setPageMark();

    

}

}