Image与Bitmap的区别及相互转换

1. Image.FromFile()返回的是某个继承自Image的具体类的对象，在这里，就是Bitmap或者Metafile其中之一。这应该算是factory pattern的一种形式。所以，Image类确实不能直接创建对象的，但这里Image.FromFile()返回的是Bitmap或者Metafile的对象。

2. Bitmap不仅仅对应于bmp，其实只要是像素式的图片格式（矢量格式不行），理论上都可以用Bitmap，就像YJPC789(雪地里的一颗星) 所说的。Image所抽象的是Bitmap和Metafile两个子类，你可以看一下msdn里的介绍。

/// <summary>
/// 将图片Image转换成Byte[]
/// </summary>
/// <param name="Image">image对象</param>
/// <param name="imageFormat">后缀名</param>
/// <returns></returns>
public static byte[] ImageToBytes(Image Image, System.Drawing.Imaging.ImageFormat imageFormat)
{

    if (Image == null) { return null; }

    byte[] data = http://www.cnblogs.com/peasana/archive/2012/02/13/null;

    using (MemoryStream ms= new MemoryStream())
    {

         using (Bitmap Bitmap = new Bitmap(Image))
        {

            Bitmap.Save(ms, imageFormat);

            ms.Position = ;

            data = http://www.cnblogs.com/peasana/archive/2012/02/13/new byte[ms.Length];

            ms.Read(data, , Convert.ToInt32(ms.Length));

            ms.Flush();

        }

    }

    return data;

}

    /// <summary>
/// byte[]转换成Image
/// </summary>
/// <param name="byteArrayIn">二进制图片流</param>
/// <returns>Image</returns>
public static System.Drawing.Image byteArrayToImage(byte[] byteArrayIn)
{
    if (byteArrayIn == null)
        return null;
    using (System.IO.MemoryStream ms = new System.IO.MemoryStream(byteArrayIn))
    {
        System.Drawing.Image returnImage = System.Drawing.Image.FromStream(ms);
        ms.Flush();
        return returnImage;
    }
}

//Image转换Bitmap
. Bitmap img = new Bitmap(imgSelect.Image);
. Bitmap bmp = (Bitmap)pictureBox1.Image;

//Bitmap转换成Image

using System.IO;

private static System.Windows.Controls.Image Bitmap2Image(System.Drawing.Bitmap Bi)
{
    MemoryStream ms = new MemoryStream();
    Bi.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
    BitmapImage bImage = new BitmapImage();
    bImage.BeginInit();
    bImage.StreamSource = new MemoryStream(ms.ToArray());
    bImage.EndInit();
    ms.Dispose();
    Bi.Dispose();
    System.Windows.Controls.Image i = new System.Windows.Controls.Image();
    i.Source = bImage;
    return i ;
}
//byte[] 转换 Bitmap
public static Bitmap BytesToBitmap(byte[] Bytes)
{
    MemoryStream stream = null;
    try
    {
        stream = new MemoryStream(Bytes);
        return new Bitmap((Image)new Bitmap(stream));
    }
    catch (ArgumentNullException ex)
    {
        throw ex;
    }
    catch (ArgumentException ex)
    {
        throw ex;
    }
    finally
    {
        stream.Close();
    }
}  

//Bitmap转byte[]
public static byte[] BitmapToBytes(Bitmap Bitmap)
{
    MemoryStream ms = null;
    try
    {
        ms = new MemoryStream();
        Bitmap.Save(ms, Bitmap.RawFormat);
        byte[] byteImage = new Byte[ms.Length];
        byteImage = ms.ToArray();
        return byteImage;
    }
    catch (ArgumentNullException ex)
    {
        throw ex;
    }
    finally
    {
        ms.Close();
    }
}

参考文章

Byte[]、Image、Bitmap 之间的相互转换

hujiiori， C#中，Image与Bitmap的区别？