Compressing JPGs which method should I use ?

[trevski]

So I am using
Dim optimizer As New ImageMagick.ImageOptimizers.JpegOptimizer()

     If bLossless Then
                        optimizer.LosslessCompress(imgfileInfo)
                    Else
                        optimizer.OptimalCompression = True
                        optimizer.Progressive = True                            
                            optimizer.Compress(imgfileInfo)                        
                    End If

Neither give me any reduction in filesize however when I use

         Using mi As ImageMagick.MagickImage = New ImageMagick.MagickImage(imgfileInfo.FullName, ImageMagick.MagickFormat.Jpg)
                            mi.Format = mi.Format ' Get Or Set the format Of the image.
                        mi.Quality = 75
                        mi.Write(imgfileInfo.FullName)
                        End Using

I get a significant drop in file-size

[dlemstra]

It all depends on what you want to do with your images. If you change the quality you will change how the image looks. And the ImageOptimizers will not change how your image looks so this means that the size will probably be larger then when you change the quality and re-encode the image.

[jdang67]

Can someone write this component and share some sample code on how to perform image quality reduction?