Bug in GetThumbnailImage method?

[nemaroller]

The image loads halfway or so.... with the last loaded vertical line clipped... (see attached picture)...

What's the deal with this?

Dim r As Drawing.Image
        r = Drawing.Image.FromStream(ms)
        Dim dummyCallBack As System.Drawing.Image.GetThumbnailImageAbort
        dummyCallBack = New _
         System.Drawing.Image.GetThumbnailImageAbort(AddressOf DummyImagePointer)
        Dim thumbNailImg As System.Drawing.Image
        Dim g As Drawing.Size
        g = r.PhysicalDimension.ToSize
        Dim c As Double
        c = g.Width / 100
        thumbNailImg = r.GetThumbnailImage(100, Convert.ToInt32(g.Height / c), dummyCallBack, IntPtr.Zero)
 
        f.PictureBox1.Image = thumbNailImg
 
'this function forces continued execution of the getThumnailImage function
Public Function DummyImagePointer() As Boolean
        Return False
End Function