I have a bitmap object I want to return as a JPEG image with a compression
set at 90% and progressive passes enabled, how can I do this in .NET 2.0?
Progressive passes are not necessary but the compression ratio is.. thanks!

You might find something useful in this class I created.

Imports System.Drawing
Imports System.Drawing.Imaging
Imports System.IO
Imports MultiBoxControl

Public Class CvImage

    Private codecs() As ImageCodecInfo

    Public Sub New()
        'Get the list of available encoders
        Static Init As Boolean = True
        If Init Then codecs = ImageCodecInfo.GetImageEncoders() : Init = False
    End Sub
    Public Function ImageToJpeg(ByVal img As Image, Optional ByVal quality
As Integer = 100) As Image
        Dim ici As ImageCodecInfo = get_Codec("image/jpeg")
        Dim ep As EncoderParameters = New EncoderParameters(1)
        'Set Quality Parameter
        ep.Param(0) = New EncoderParameter(Encoder.Quality, quality)
        'Save to a Memory Stream
        Dim s As New System.IO.MemoryStream
        img.Save(s, ici, ep)
        Return img.FromStream(s)
    End Function

    Public Function BmpToJpegToBytes(ByVal BitMapIn As Bitmap, ByVal Quality
As Integer, Optional ByVal CompressPct As Integer = -1) As Byte()
        Return BmpToJpegToStream(BitMapIn, Quality).ToArray
    End Function

    Public Function BmpToJpegToImage(ByVal BitMapIn As Bitmap, ByVal Quality
As Integer) As Image
        Return Image.FromStream(BmpToJpegToStream(BitMapIn, Quality))
    End Function

    Public Function BmpToJpegToStream(ByVal BitMapIn As Bitmap, ByVal
Quality As Integer, Optional ByVal CompressPct As Integer = -1) As
IO.MemoryStream
        'find the encoder with the image/jpeg mime-type
        Dim ici As ImageCodecInfo = get_Codec("image/jpeg")
        'Create a collection of encoder parameters (we only need one in the
collection)
        Dim ep As EncoderParameters = New EncoderParameters(1)
        'Set Quality Parameter
        ep.Param(0) = New EncoderParameter(Encoder.Quality, Quality)
        'ep.Param(0) = New EncoderParameter(Encoder.Compression, CompressPct)

        'Converting to a MemoryStream using GetBuffer
        Dim s As New System.IO.MemoryStream
        Dim byt() As Byte
        'BitMapIn.Save(s, Imaging.ImageFormat.Jpeg)
        BitMapIn.Save(s, ici, ep)

        'Converting to a MemoryStream using Read
        'Dim ms As New System.IO.MemoryStream
        'BitMapIn.Save(ms, ici, ep)
        'Dim byt(CInt(s.Length() - 1)) As Byte
        's.Position = 0L
        's.Read(byt, 0, byt.Length)

        'Converting to a File
        'BitMapIn.Save("c:\testbitmap.jpg", ici, ep)
        'Dim fs As New System.IO.FileStream("c:\testbitmap.jpg",
IO.FileMode.Open, IO.FileAccess.Read)
        'Dim byt(CInt(fs.Length() - 1)) As Byte
        'fs.Read(byt, 0, byt.Length)
        'fs.Close()
        Return s
    End Function

    Public Function IconToBitmap(ByVal in_colour As Color, ByVal in_icon As
Icon) As Bitmap
        Dim g As Graphics
        Dim b As Bitmap
        Dim c As Color
        b = New Bitmap(in_icon.Width, in_icon.Height,
System.Drawing.Imaging.PixelFormat.Format32bppPArgb)
        g = Graphics.FromImage(b)
        g.FillRectangle(New SolidBrush(Color.Transparent), New Rectangle(0,
0, b.Width, b.Height))
        g.DrawIcon(in_icon, 0, 0)
        g.Dispose()
        Return b
    End Function

    Public Function GetNewImgSize(ByVal OldImage As Image, ByVal MxSz As
Size) As Size
        Dim w As Integer = OldImage.Width
        Dim h As Integer = OldImage.Height
        Dim nw, nh As Integer
        Dim pctw, pcth As Double
        If w < MxSz.Width Then
            pctw = 1
        Else
            pctw = MxSz.Width / w
        End If
        If h < MxSz.Height Then
            pcth = 1
        Else
            pcth = MxSz.Height / h
        End If
        If pctw < pcth Then
            nw = CInt(pctw * w)
            nh = CInt(pctw * h)
        Else
            nw = CInt(pcth * w)
            nh = CInt(pcth * h)
        End If
        Return New Size(nw, nh)
    End Function
    Public Function ConvImageBytesToMemoryStream(ByVal origimgbytes() As
Byte, ByVal NewType As String, Optional ByVal qualitypct As Integer = 100) As
MemoryStream
        Dim ici As ImageCodecInfo = get_Codec(newtype)
        Dim img As Image
        If ici Is Nothing Then Return Nothing
        Dim s As New System.IO.MemoryStream
        Dim os As New System.IO.MemoryStream(origimgbytes)
        Try
            Dim ep As EncoderParameters = New EncoderParameters(1)
            'Set Quality Parameter
            ep.Param(0) = New EncoderParameter(Encoder.Quality, qualitypct)
            'Save to a Memory Stream
            img = Image.FromStream(os)
            'Convert and save to image
            img.Save(s, ici, ep)
            Return s
        Catch ex As Exception
            Throw New Exception(ex.Message)
        Finally
            os.Close()
        End Try
    End Function
    Public Function ConvImageBytesToBytes(ByVal origimgbytes() As Byte,
ByVal NewType As String, Optional ByVal qualitypct As Integer = 100) As Byte()
        Dim s As MemoryStream = ConvImageBytesToMemoryStream(origimgbytes,
NewType, qualitypct)
        Dim b(CInt(s.Length - 1)) As Byte
        b = s.GetBuffer()
        s.Close()
        Return b
    End Function

    Public Function ConvImageToImage(ByVal img As Image, ByVal NewType As
String, Optional ByVal quality As Integer = 100) As Image
        Dim ici As ImageCodecInfo = get_Codec(NewType)
        If ici Is Nothing Then Return Nothing
        Dim ep As EncoderParameters = New EncoderParameters(1)
        'Set Quality Parameter
        ep.Param(0) = New EncoderParameter(Encoder.Quality, quality)
        'Save to a Memory Stream
        Dim s As New System.IO.MemoryStream
        Try
            img.Save(s, ici, ep)
            Return img.FromStream(s)
        Catch ex As ExecutionEngineException
            Throw New Exception(ex.Message)
        Finally
            s.Close()  'NOTE: may need to keep s open
        End Try
    End Function
    Public Function ConvImageToBytes(ByVal img As Image, ByVal NewType As
String, Optional ByVal quality As Integer = 100) As Byte()

        '        Dim newimg As Image = ConvImageToImage(img, NewType, quality)
        'dim b() as Byte = img.
    End Function
    Public Function ConvBytesToImage(ByVal b() As Byte) As Image
        'Note that memorystream must remain open for the life of the image
        Dim picbuffer As System.IO.MemoryStream = New
System.IO.MemoryStream(b)
        Return Image.FromStream(picbuffer, False)
        picbuffer.Close()
    End Function
    Private Function get_Codec(ByVal type As String) As ImageCodecInfo
        Dim mime As String = SetMime(type)
        If mime Is Nothing Then Return Nothing
        For Each codec As ImageCodecInfo In codecs
            If (codec.MimeType = mime) Then
                Return codec
            End If
        Next
        Return Nothing
    End Function
    Public Function SetMime(ByVal imagetype As String) As String
        Select Case imagetype.ToLower.Trim
            Case "jpg", "jpeg", "image/jpg", "image/jpeg"
                Return "image/jpeg"
            Case "bmp", "image/bmp"
                Return "image/bmp"
            Case "gif", "image/gif"
                Return "image/gif"
            Case "tif", "tiff", "image/tif", "image/tiff"
                Return "image/tiff"
            Case "png", "image/png"
                Return "image/png"
            Case Else
                Return Nothing
        End Select
    End Function


    Public Function SaveImageBytesToFile(ByVal b() As Byte, ByVal imagetype
As String, ByVal dialog As SaveFileDialog) As Boolean
        'Returns True if saved, false if not
        'Displays error message if not saved
        'imagetype = "jpg", etc.
        Dim fname As String
        Dim typname As String
        Dim t As String
        Dim filterindex As Integer
        Dim mime As String = SetMime(imagetype)

        Select Case mime
            Case "image/jpeg" : filterindex = 1
            Case "image/bmp" : filterindex = 2
            Case "image/gif" : filterindex = 3
            Case "image/tiff" : filterindex = 4
            Case "image/png" : filterindex = 5
            Case Else : filterindex = 1
        End Select
        Dim fs As FileStream
        Dim w As BinaryWriter
        Try
            'Get Picture File Name
            With dialog
                .Filter = "Joint Photographic Experts Group (*.jpeg)|*.jpg|"
& "BitMap (*.bmp)|*.bmp|" & "Graphics Interchange Format (*.gif)|*.gif|" &
"TagImage (*tif)|*.tif|" & "Portable Network Graphics (*png)|*.png"
                .Title = "Select Picture File...:"
                .FilterIndex = filterindex
                .InitialDirectory = InitSet.PictureSourcePath
                .CheckFileExists = False
                .CheckPathExists = True
                .OverwritePrompt = True
                .AddExtension = True
                .ValidateNames = True
            End With
            If dialog.ShowDialog() = DialogResult.OK Then
                fname = dialog.FileName
                Dim fi As New FileInfo(fname)
                InitSet.PictureSourcePath = fi.DirectoryName
                SerializeSettings()
                t = SetMime(fi.Extension.Trim("."c).ToLower)
                If t <> mime Then
                    If MultiBox.Show("Current Picture is in """ & mime & """
format...Wish to Change to """ & t & """ format?", "Change Format...",
MultiBoxButtons.YesNo, MultiBoxImage.Question) = MultiBoxResult.No Then
                        Return False
                    Else
                        b = ConvImageBytesToBytes(b, t, 100)
                    End If
                End If
                fs = New FileStream(fname, FileMode.OpenOrCreate)
                fs.SetLength(b.Length)
                w = New BinaryWriter(fs)
                w.Write(b)
                MultiBox.Show("Picture saved to """ & fname & """
successfully!", "Image Saved...", MultiBoxButtons.Ok,
MultiBoxImage.Information)

            Else
                fname = Nothing
            End If
        Catch ex As Exception
            Throw New Exception("Image not saved due to error:" & DvbLF &
ex.Message)
        Finally
            If Not w Is Nothing Then w.Close()
            If Not fs Is Nothing Then fs.Close()
            If Not dialog Is Nothing Then dialog.Dispose()
        End Try
    End Function

End Class

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