Question

Is there any difference when you load into bitmap the same image from bmp or from png (or other format)? Does the original image format influence Bitmap object size in RAM?

Is there a way to archive Bitmap objects in order to make them less RAM resources consuming?

Answer 1

There are two ways to save the data in memory

1. Serialize and compress object with GZipStream in memory
2. Save images to temporary directory and read them to ram if only needed.

Image object size is not influenced with the original image format. but the size of the stream , that saves the object – does.

Here is the way how to get stream from the object:

 public static Stream GetPNGBitmapStream(Image initial)
    {
        return GetBitmapStream(initial, "image/PNG");
    }

    public static Stream GetJPGBitmapStream(Image initial)
    {
        return GetBitmapStream(initial, "image/jpeg");
    }

    private static Stream GetBitmapStream(Image initial, string mimeType)
    {
        MemoryStream ms = new MemoryStream();

        var qualityEncoder = Encoder.Quality;
        var quality = (long)90;
        var ratio = new EncoderParameter(qualityEncoder, quality);
        var codecParams = new EncoderParameters(1);
        codecParams.Param[0] = ratio;
        ImageCodecInfo[] infos = ImageCodecInfo.GetImageEncoders();

        ImageCodecInfo jpegCodecInfo = null;
        for (int i = 0; i < infos.Length; i++)
        {
            if (string.Compare(infos[i].MimeType, mimeType,true) == 0)
            {
                jpegCodecInfo = infos[i];
                break;
            }
        }

        if (jpegCodecInfo != null)
        {
            initial.Save(ms, jpegCodecInfo, codecParams); 
            MemoryStream ms2 = new MemoryStream(ms.ToArray());
            ms.Close();
            ms.Dispose();
            return ms2;
        }

        return null;
    }