resize image function outputs a distorted image

I have a function that I want to pass the image and size to resize image. The issue I am seeing is that the original image looks very clear but the resized image is very distorted. I could see for a image enlarging but I am resizing to a much smaller image.

Here is my function:

Code:

---

Public Function ResizeImage(ByVal sFileName As String, Optional iWidth As Integer = 230, Optional iHeight As Integer = 320) As Byte()

        Dim sFullFilePath As String = "http://www.domain.com/images/" & sFileName
        Dim _width As Integer = iWidth
        Dim _height As Integer = iHeight

        'Set maximum width and height of image
        Dim MaxWidth As Integer = _width
        Dim MaxHeight As Integer = _height

        'Create a plain white box
        Dim BlankImg As Bitmap = New Bitmap(_width, _height)
        Dim BlankGraphic As Graphics = Graphics.FromImage(BlankImg)
        BlankGraphic.FillRectangle(Brushes.White, New Rectangle(0, 0, BlankImg.Width, BlankImg.Height))
        BlankGraphic.InterpolationMode = Drawing.Drawing2D.InterpolationMode.HighQualityBicubic
        BlankGraphic.SmoothingMode = Drawing.Drawing2D.SmoothingMode.HighQuality
        BlankGraphic.PixelOffsetMode = Drawing.Drawing2D.PixelOffsetMode.HighQuality
        BlankGraphic.CompositingQuality = Drawing.Drawing2D.CompositingQuality.HighQuality

        'Load image from web to add to new Bitmap
        Dim oPost As WebPost = New WebPost
        Dim s As Stream = New MemoryStream(oPost.SaveImageToByte(sFullFilePath)) 'download image to stream
        Dim OriginalImg As Bitmap = System.Drawing.Bitmap.FromStream(s)
        Dim ImgFormat As ImageFormat = OriginalImg.RawFormat  'grab the images format to save bitmap as later

        'Resize image if either width or height is larger than the maximum allowed
        Dim iDiff As Integer = 0
        Dim newX As Integer = 0 'Set the new top left drawing position on the image canvas
        Dim newY As Integer = 0
        Dim wRatio As Decimal = 0
        Dim newWidth As Integer = _width
        Dim newHeight As Integer = _height

        If (OriginalImg.Width > MaxWidth) Or (OriginalImg.Height > MaxHeight) Then

            'Need to determine what dimension is larger.
            Dim iWidthDiff As Integer = OriginalImg.Width - MaxWidth
            Dim iHeigthDiff As Integer = OriginalImg.Height - MaxHeight

            If iWidthDiff > iHeigthDiff Then
                iDiff = OriginalImg.Width - MaxWidth
                newHeight = Convert.ToInt64(OriginalImg.Height - ((iDiff / OriginalImg.Width) * OriginalImg.Height))
                newWidth = MaxWidth
                newX = 0
                newY = Int((_height - newHeight) / 2)

            Else
                iDiff = OriginalImg.Height - MaxHeight
                newWidth = Convert.ToInt64(OriginalImg.Width - ((iDiff / OriginalImg.Height) * OriginalImg.Width))
                newHeight = MaxHeight
                newX = Int((_width - newWidth) / 2)
                newY = 0

            End If
        Else
            newHeight = OriginalImg.Height
            newWidth = OriginalImg.Width
            newX = Int((_width - newWidth) / 2) 'Position the image centrally across the canvas
            newY = Int((_height - newHeight) / 2) 'Position the image centrally down the canvas

        End If

        'Add original image to graphic
        BlankGraphic.DrawImage(OriginalImg, newX, newY, newWidth, newHeight)

        Dim codecEncoder As ImageCodecInfo
        codecEncoder = GetEncoder("image/jpeg")

        Dim quality As Integer = 100
        Dim encodeParams As New EncoderParameters(1)
        Dim qualityParam As New EncoderParameter(Imaging.Encoder.Quality, quality)
        encodeParams.Param(0) = qualityParam

        Dim imageBytes As Byte() = Nothing
        Using memoryStream As New MemoryStream()
            BlankImg.Save(memoryStream, codecEncoder, encodeParams)
            imageBytes = memoryStream.ToArray()
        End Using

        Return imageBytes

    End Function

Function GetEncoder(ByVal mimeType As String) As ImageCodecInfo
        Dim codec As ImageCodecInfo
        Dim RetCodec As ImageCodecInfo = Nothing

        Dim codecs() As ImageCodecInfo = ImageCodecInfo.GetImageEncoders()
        For Each codec In codecs
            If codec.MimeType = mimeType Then
                RetCodec = codec
            End If
        Next

        Return RetCodec
    End Function

---

Here is how I am calling this:

Code:

---

Dim oImgFunc As image_functions = New image_functions
Dim s As Byte() = oImgFunc.ResizeImage(sSrcImg, 140, 170)
Dim imgItem As iTextSharp.text.Image = iTextSharp.text.Image.GetInstance(s)
pCell.AddElement(New Phrase(New Chunk(imgItem, 0, 0)))

---

This version returns much clearer but images can be distorted because unlike the ResizeImage which will re-size proportionally.

Code:

---

Dim sFullImgUrl As String = "http://www.domain.com/images/" & sSrcImg
Dim oPost As WebPost = New WebPost
Dim s As Stream = New MemoryStream(oPost.SaveImageToByte(sFullImgUrl))
Dim imgItem As iTextSharp.text.Image = iTextSharp.text.Image.GetInstance(s)

imgItem.ScaleAbsolute(140, 170)
imgItem.SetDpi(140, 170)
pCell.AddElement(New Phrase(New Chunk(imgItem, 0, 0)))

---

Any ideas why my ResizeImage isn't returning a clear image?