将Image转换为Icon

/// <summary>
/// 将Image转换为Icon
/// </summary>
/// <param name="image">要转换为图标的Image对象</param>
/// <param name="nullTonull">当image为null时是否返回null。false则抛空引用异常</param>
/// <exception cref="ArgumentNullException" />
public static Icon ConvertToIcon(Image image, bool nullTonull = false)
{
    if (image == null)
    {
        if (nullTonull) { return null; }
        throw new ArgumentNullException("image");
    }

    using (MemoryStream msImg = new MemoryStream()
                      , msIco = new MemoryStream())
    {
        image.Save(msImg, ImageFormat.Png);

        using (var bin = new BinaryWriter(msIco))
        {
            //写图标头部
            bin.Write((short)0);           //0-1保留
            bin.Write((short)1);           //2-3文件类型。1=图标, 2=光标
            bin.Write((short)1);           //4-5图像数量（图标可以包含多个图像）

            bin.Write((byte)image.Width);  //6图标宽度
            bin.Write((byte)image.Height); //7图标高度
            bin.Write((byte)0);            //8颜色数（若像素位深>=8，填0。这是显然的，达到8bpp的颜色数最少是256，byte不够表示）
            bin.Write((byte)0);            //9保留。必须为0
            bin.Write((short)0);           //10-11调色板
            bin.Write((short)32);          //12-13位深
            bin.Write((int)msImg.Length);  //14-17位图数据大小
            bin.Write(22);                 //18-21位图数据起始字节

            //写图像数据
            bin.Write(msImg.ToArray());

            bin.Flush();
            bin.Seek(0, SeekOrigin.Begin);
            return new Icon(msIco);
        }
    }
}