Vb.net bitmap blurred when saved

See more:

VB

Bitmap

drawing

hello once again !

could someone tell me how could i save an image that i drew (painted) on it with the same image quality as the original image ?

i'm using this code to save the image :

Using Bmp As New Bitmap(PictureBox4.Image, defaultWidth, defaultHeight)

            Using G As Graphics = Graphics.FromImage(Bmp)

                G.InterpolationMode = Drawing2D.InterpolationMode.NearestNeighbor
                G.PixelOffsetMode = Drawing2D.PixelOffsetMode.Half

                G.DrawImage(Bmp, 0, 0, defaultWidth, defaultHeight)

                Bmp.Save(str1 & "\" & str2, Imaging.ImageFormat.Jpeg)
                Dim myCallback As New Image.GetThumbnailImageAbort(AddressOf ThumbnailCallback)
                Dim myBitmap As New Bitmap(Drawbitmap)
                Dim myThumbnail As Image = myBitmap.GetThumbnailImage(100, 60, myCallback, IntPtr.Zero)
                myThumbnail.Save(str1.Replace("Saved", "Thumbnails") & "\" & str2)
                Bmp.Dispose()

            End Using
        End Using

the thing is the original image has 1920x1080 ,when i load the image into a picturebox i use the bellow code to scale the bitmap to fit the picturebox :

Dim PicBoxHeight As Integer
        Dim PicBoxWidth As Integer
        Dim ImageHeight As Integer
        Dim ImageWidth As Integer
        Dim TempImage As Image
        Dim scale_factor As Single
        PictureBox4.SizeMode = PictureBoxSizeMode.Normal
        ' Get control size
        PicBoxHeight = PictureBox4.Height
        PicBoxWidth = PictureBox4.Width
        ' Load the image. Change Image.FromFile() to match your code
        TempImage = Image.FromFile(str)
        defaultWidth = TempImage.Width
        defaultHeight = TempImage.Height
        ' Get image size
        ImageHeight = TempImage.Height
        ImageWidth = TempImage.Width
        ' Calculate scale_factor
        scale_factor = 1.0 ' No scaling by default i.e. image fits in the Box
        ' 1) Height
        If ImageHeight > PicBoxHeight Then
            ' Reduce height first
            scale_factor = CSng(PicBoxHeight / ImageHeight)
        End If
        ' 2) Width. Notice, we do know now how much we have to scale down the height
        ' and the scale_factor affects width too
        If (ImageWidth * scale_factor) > PicBoxWidth Then
            ' Scaled width exceeds Box's width, recalculate scale_factor
            scale_factor = CSng(PicBoxWidth / ImageWidth)
        End If
        ' Move image to control for resizing
        PictureBox4.Image = TempImage
        ' Get the source bitmap.
        Dim bm_source As New Bitmap(PictureBox4.Image)
        ' Make a bitmap for the result.
        Dim bm_dest As New Bitmap( _
            CInt(bm_source.Width * scale_factor), _
            CInt(bm_source.Height * scale_factor))

        ' Make a Graphics object for the result Bitmap.
        Dim gr_dest As Graphics = Graphics.FromImage(bm_dest)
        ' Copy the source image into the destination bitmap.
        gr_dest.DrawImage(bm_source, 0, 0, _
            bm_dest.Width + 1, _
            bm_dest.Height + 1)
        ' Display the result.
        PictureBox4.Image = bm_dest

As you can see the image it's scaled to a lower resolution and when i finish drawing on it and click the save button , it re-sizes the bitmap to the original's image

Using Bmp As New Bitmap(PictureBox4.Image, defaultWidth, defaultHeight)

resolution and saves the image . But the image is saved with a blur over it and each time i re-save that image it keeps adding more blur to it. How could i prevent the blur from applying on the saved image.Thank you !