Hello @Kuki_Force ,
Please try this:
Public Sub AddImageToPage(doc As PPTXDocument, logoPath As [String], x As Single, y As Single)
Dim img As New REImage(logoPath)
For i As Integer = 0 To doc.GetPageCount() - 1
Dim tmp As PPTXPage = DirectCast(doc.GetPage(i), PPTXPage)
' Add REImage to the PPTXPage and embed it in the form of Jpeg.
tmp.AddImage(img, x, y, PPTUnits.[Default], ImageFormat.Jpeg)
Next
End Sub
Source: http://www.rasteredge.com/how-to/vb-net-imaging/powerpoint-add-image/
Hope it helps!
Best regards,
Marius