I have ever googled a tutorial for
adding image to PDF document page. Below demo code is what I have used before. I used it to draw a bmp image on accurately specified location on my PDF document page. You may have a try and you can modify the sample code based on your needs.
Public Shared FolderName As String = "c:/"
Private Sub button1_Click(sender As Object, e As EventArgs)
Dim fileName As String = FolderName & "Sample.pdf"
Dim doc As REDocument = REFile.OpenDocumentFile(fileName, New PDFDecoder())
'use PDFDecoder open a pdf file
Dim rePage As REPage = DirectCast(doc.GetPage(0), REPage)
Dim width As Integer = 100
Dim height As Integer = 60
''' data[]: a byte array to contain color data (as same format as Image Data PixelArray in BMP file)
''' caller must provide correct color data; otherwise, unpredictable error may happen
Dim data As Byte() = New Byte(width * height * 3 - 1) {}
' set bottom 20 lines to red
For rowIdx As Integer = 0 To 19
For i As Integer = 0 To width - 1
data(width * rowIdx * 3 + i * 3 + 2) = &Hff
Next
Next
' set top 10 lines to blue
For rowIdx As Integer = 0 To 9
For i As Integer = 0 To width - 1
data(width * (height - 1 - rowIdx) * 3 + i * 3) = &Hff
Next
Next
Dim reImage As New REImage(width, height, ImageMode.RGB888, data)
REFile.SaveDocumentFile(doc, "c:/reimage.pdf", New PDFEncoder())
End Sub