VB.NET Code:

Public Class SaveResizedImage

    ' SaveResizedImage
    Public Sub SaveResizedImage(ByVal objGraphic As System.Drawing.Image, ByVal strPath As String, ByVal intWidth As Integer)

        Dim objFormat As System.Drawing.Imaging.ImageFormat = objGraphic.RawFormat

        Dim objThumbSize As New System.Drawing.Size
        objThumbSize = GetSize(objGraphic.Width, objGraphic.Height, intWidth)

        Dim objBmp As System.Drawing.Bitmap = CreateThumbnail(objGraphic, objThumbSize.Width, objThumbSize.Height)

        If objFormat Is System.Drawing.Imaging.ImageFormat.Gif Then
            objBmp.Save(strPath, System.Drawing.Imaging.ImageFormat.Gif)
        Else
            objBmp.Save(strPath, System.Drawing.Imaging.ImageFormat.Jpeg)
        End If

        objBmp.Dispose()

    End Sub ' SaveResizedImage

    ' GetSize
    Private Function GetSize(ByVal dblWidth As Double, ByVal dblHeight As Double, ByVal intWidth As Integer) As System.Drawing.Size

        Dim dblNewWidth As Double
        Dim dblNewHeight As Double

        dblNewWidth = intWidth
        ' Set new height, preserve original width/height ratio
        dblNewHeight = dblHeight * dblNewWidth / dblWidth

        Dim NewSize As New System.Drawing.Size(CInt(dblNewWidth), CInt(dblNewHeight))

        Return NewSize

    End Function ' GetSize

    ' CreateThumbnail
    Private Function CreateThumbnail(ByVal objGraphic As System.Drawing.Image, ByVal lnWidth As Integer, ByVal lnHeight As Integer) As System.Drawing.Bitmap

        Dim bmpOut As System.Drawing.Bitmap = Nothing

        Try
            Dim loBMP As New System.Drawing.Bitmap(objGraphic)
            Dim loFormat As System.Drawing.Imaging.ImageFormat = loBMP.RawFormat
            Dim lnRatio As Decimal
            Dim lnNewWidth As Integer = 0
            Dim lnNewHeight As Integer = 0

            If loBMP.Width < lnWidth AndAlso loBMP.Height < lnHeight Then
                Return loBMP
            End If

            If loBMP.Width > loBMP.Height Then
                lnRatio = CType(lnWidth, Decimal) / loBMP.Width
                lnNewWidth = lnWidth
                Dim lnTemp As Decimal = loBMP.Height * lnRatio
                lnNewHeight = CType(lnTemp, Integer)
            Else
                lnRatio = CType(lnHeight, Decimal) / loBMP.Height
                lnNewHeight = lnHeight
                Dim lnTemp As Decimal = loBMP.Width * lnRatio
                lnNewWidth = CType(lnTemp, Integer)
            End If

            bmpOut = New System.Drawing.Bitmap(lnNewWidth, lnNewHeight)
            Dim g As System.Drawing.Graphics = System.Drawing.Graphics.FromImage(bmpOut)
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic
            g.FillRectangle(System.Drawing.Brushes.White, 0, 0, lnNewWidth, lnNewHeight)
            g.DrawImage(loBMP, 0, 0, lnNewWidth, lnNewHeight)
            loBMP.Dispose()

        Catch
            Return Nothing
        End Try

        Return bmpOut

    End Function ' CreateThumbnail

End Class