How to optimize an image for web?

What image formats?

A simple way to compress images is to use the namespace classes System.Drawing :

public static void ComprimirImagem(Image imagem, long qualidade, string filepath)
{
    var param = new EncoderParameters(1);
    param.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qualidade);
    var codec = ObterCodec(imagem.RawFormat);
    imagem.Save(filepath, codec, param);
}

private static ImageCodecInfo ObterCodec(ImageFormat formato)
{
    var codec = ImageCodecInfo.GetImageDecoders().FirstOrDefault(c => c.FormatID == formato.Guid);
    if (codec == null) throw new NotSupportedException();
    return codec;
}

Adapted from here .

Theoretically the code would work with any image format that the system had codec, but according to my tests only with JPEG images there was compression (the others remained the same size regardless of the quality passed).

I did some testing with this image (265.94 KB), the results were:

• Quality 80L : 54.3 KB ( image )
• Quality 60L : 40.6 KB ( image )
• Quality 40L : 33.5 KB ( image )
• Quality 20L : 25.4 KB ( image )

PS: The images of the posted links do not represent exactly the quality I got in my tests, since the imgur also made its own optimization; it's just to get a sense of quality loss.

Other references

• The ImageResizer library ( NuGet / a>) has some compression methods .
• TinyPNG has a API (free until 500 images / month).
• Dot Net Perls has a tutorial on png optimization (using the OptiPNG ).

The example of talles, okay, the conversion to the other models just in the formed pass as the code below.

var codec = ImageCodecInfo.GetImageDecoders().First(c => c.FormatID == ImageFormat.Jpeg.Guid);