Adding image to existing PDF (vb.net) - vb.net

Question

We have a program that generates PDF documents, the staff member who uses these documents needs to hand sign all the generated pages (some 700+). What I would like to do is have a scaned image of his signature and insert it on every page in the existing PDF.
My question thus is how is this done easyest ussing vb.net

Answer 1

You can automate that process by using a PDF editing library. Use for example the PDFLib 2.1 which is an open source project. Download it from here http://pdflib.codeplex.com/ and try editing your pages.
It exposes a function named GetPages which returns a list of the PDF pages. By iterating through every page, you can edit it or add new content to it.

Answer 2

You can quite easily add an image to all pages of a PDF with help of Docotic.Pdf library.
Here is sample code (VB.NET):
Public Shared Sub AddImageToAllPages()
Using pdf As New PdfDocument("input.pdf")
Dim image As PdfImage = pdf.AddImage("image.png")
For Each page As PdfPage In pdf.Pages
page.Canvas.DrawImage(image, 100, 100)
Next
pdf.Save("out.pdf")
End Using
End Sub
and here is the same for C#:
public static void AddImageToAllPages()
{
using (PdfDocument pdf = new PdfDocument("input.pdf"))
{
PdfImage image = pdf.AddImage("image.png");
foreach (PdfPage page in pdf.Pages)
page.Canvas.DrawImage(image, 100, 100);
pdf.Save("out.pdf");
}
}
The code will open PDF, open image and add the image to all pages of the PDF. The image will be reused, so the PDF byte length won't be increased too much. Only one copy of the added image will be stored in output PDF.
Disclaimer: I work for vendor of the library.