REDIM PROPORTIONNEL D’UN FICHIER IMAGE.

Private Function Redim_Image(ByVal vStr_PathOrigine As String, ByVal vStr_PathDestination As String, ByVal vInt_Width As Integer) As String
        Try
            'test si fichier existe
            If Not IO.File.Exists(vStr_PathOrigine) Then
                Return "Le fichier [" & vStr_PathOrigine & "] n'existe pas."
                Exit Function
            End If
            'test le type image
            Dim F As New IO.FileInfo(vStr_PathOrigine)

            Select Case F.Extension.ToLower
                Case ".gif", ".jpg", "jpeg", ".bmp"
                    'ras c bon
                Case Else
                    Return "Les fichier image d'origne doit avoir l'extension [.gif], [.jpg], [jpeg] ou [.bmp]"
                    Exit Function
            End Select
            F = Nothing

            'effacer destination
            If IO.File.Exists(vStr_PathDestination) Then IO.File.Delete(vStr_PathDestination)

            'charge image d'origine
            Dim Img As Drawing.Image
            Img = Drawing.Image.FromFile(vStr_PathOrigine)

            Dim Int_Height As Integer = vInt_Width * Img.Height / Img.Width

            Dim B As New Bitmap(vInt_Width, Int_Height)
            Dim G As Graphics = Graphics.FromImage(B)
            G.InterpolationMode = Drawing2D.InterpolationMode.HighQualityBilinear
            G.DrawImage(Img, 0, 0, vInt_Width, Int_Height)
            B.Save(vStr_PathDestination, Drawing.Imaging.ImageFormat.Jpeg)

            Return String.Empty
        Catch ex As Exception
            Return ex.Message
        End Try

End Function