从PDF中删除图像或图层

Question

is it possible to remove an Image from PDF-File previous added by tcpdf:

$pdf->Image();

Or remove a layer which was added by:

$pdf->startLayer('layer1', true, true);
$pdf->SetFontSize(18);
$pdf->SetTextColor(0,127,0);
$txt = 'Using the startLayer() method you can group PDF objects into layers. This text is on "layer1".';
$pdf->Write(0, $txt, '', 0, 'L', true, 0, false, false, 0);
$pdf->endLayer();