How to reduce JPEG Image size

[Nitesh]

Hi Guys,

Im using this code to resize images:

Public Class RJpeg

        Private mFileName As String
        Private mWidth As Integer
        Private mHeight As Integer

        Public Property FileName() As String
            Get
                Return mFileName
            End Get
            Set(ByVal Value As String)
                mFileName = Value
            End Set
        End Property

        Public Property NewWidth() As Integer
            Get
                Return mWidth
            End Get
            Set(ByVal value As Integer)
                mWidth = value
            End Set
        End Property

        Public Property NewHeight() As Integer
            Get
                Return mHeight
            End Get
            Set(ByVal value As Integer)
                mHeight = value
            End Set
        End Property

        Public Sub New()
            mHeight = 0
            mWidth = 0
            mFileName = ""
        End Sub

Public Sub ResizeImage()
            Dim imgOriginal As Image
            Dim OriginalHeight As Single
            Dim OriginalWidth As Single
            Dim NewWidth As Integer
            Dim NewHeight As Integer
            Dim ResizedBitmap As Bitmap
            Dim ResizedImage As Graphics
            Dim quality As Long = 40

            Dim qualityparam As New EncoderParameter(Encoder.Quality, quality)
            Dim jpegCodec As ImageCodecInfo = GetEncoderInfo("image/jpeg")

            Dim encoderParams As New EncoderParameters(1)
            encoderParams.Param(0) = qualityparam

            imgOriginal = Image.FromFile(mFileName)

            OriginalHeight = imgOriginal.Height
            OriginalWidth = imgOriginal.Width
            ' Finds height and width of resized image
            If (OriginalHeight > OriginalWidth) Then
                NewHeight = mHeight
                NewWidth = mWidth '((OriginalWidth / OriginalHeight) * NewImageSize)
            Else
                NewWidth = mWidth
                NewHeight = mHeight  '((OriginalHeight / OriginalWidth) * NewImageSize)
            End If
            ' Create new bitmap that will be used for resized image
            ResizedBitmap = New Bitmap(NewWidth, NewHeight)
            ResizedImage = Graphics.FromImage(ResizedBitmap)
            ' Resized image will have best possible quality
            ResizedImage.InterpolationMode = InterpolationMode.HighQualityBicubic
            ResizedImage.CompositingQuality = CompositingQuality.HighQuality
            ResizedImage.SmoothingMode = SmoothingMode.HighQuality
            ' Draw resized image
            ResizedImage.DrawImage(imgOriginal, 0, 0, NewWidth, NewHeight)
            ' Save thumbnail to file
            imgOriginal.Dispose()
            ResizedBitmap.Save(mFileName, jpegCodec, encoderParams)

            ' It is important to take care of memory, especially in cases 
            ' when code works with graphics

            ResizedBitmap.Dispose()
            ResizedImage.Dispose()


        End Sub
        Private Function GetEncoderInfo(ByVal mimeType As String) As ImageCodecInfo
            Dim codecs As ImageCodecInfo() = ImageCodecInfo.GetImageEncoders

            For i As Integer = 0 To codecs.Length - 1
                If codecs(i).MimeType = mimeType Then
                    Return codecs(i)
                End If
            Next

            Return Nothing
        End Function

when I use my class I pass 208 as the width and height. My images are resized fine. Say I get an image with the dimensions 394x394 and a size of 97kb.

After I resize it's dimensions are 208x208 and the size is 56kb.

I need to reduce the size of the jpeg even more to say 15kb. How can I do this?

Also, when I open the jpeg in photoshop it says "Invalid JPEG marker type". Any idea why this would happen? Please help

[dunfiddlin]

Can I suggest that you take a look at this thread here, particularly my last post, as this is basically a whole lot easier than you're making it!