HTML2PDF图片代码无效

I have following HTML code being displayed in pdf but image tag not working

$html.= "<h2>Header</h2>
";
$html.= "<p>Text</p>
";
$html.= "<img src=" . $path1 .">
";

 $pdf=new PDF_HTML();
    $pdf->SetFont('Arial','',12);
    $pdf->WriteHTML($html);
    $pdf->Output('F',$filename);

You have to use pdf->image for image to display. For Ex:-

$pdf->Image('logo.png',10,10,-300);

For referency, You can study here