压缩流中的图像

Question

I am storing images in database, before I store them, i am resizing them.

However, resizing, doesnt compress the image. Stream is same stream. I want to be able to compress the image as well.

How can I compress images which are stored in database as stream and returned to request as follows?

    public ActionResult ViewImage(int id, string imageType ="image")
    {
        ContestImage contestImage = GetContestImage(id);

        byte[] fileContent;
        string mimeType;
        string fileName;

        if (imageType == "thumb")
        {
            fileContent = contestImage.ThumbNail.Image;
            mimeType = contestImage.ThumbNail.ImageMimeType;
            fileName = contestImage.ThumbNail.ImageFileName;
        }
        else if (imageType == "image")
        {
            fileContent = contestImage.Image.Image;
            mimeType = contestImage.Image.ImageMimeType;
            fileName = contestImage.Image.ImageFileName;
        }


        return File(fileContent, mimeType, fileName);
    }

public class UserImage
{
    public virtual int Id { set; get; }
    public virtual byte[] Image { set; get; }
    public virtual string ImageMimeType { set; get; }
    public virtual string ImageFileName { set; get; }
}

ContestImage has UserImage object.

Answer 1

从数据库存储和检索图像时，您是否尝试过使用GZipStream ？

Answer 2

Two main approaches spring to mind:

• Load the data as an Image and serialize it (to a memory stream) in a compressed file format (eg png or jpeg)

• Serialize the data (to a memory stream) via a compressing stream such as DeflateStream.

Once you have the data in a MemoryStream, you can use MemoryStream.ToArray() to convert it back to a straight byte[] buffer to pass to your database.