C#读取图片/图像文件尺寸的最快方法

据我所知，从C#中的图片/图像文件中读取尺寸（宽度和高度）的最快方法是：

DateTime startDateTime = DateTime.Now;string sourceFolder = @"C:\Temp";// Get all files from sourcefolder, including subfolders.string[] sourceFiles = Directory.GetFiles(sourceFolder, "*", SearchOption.AllDirectories);foreach (string file in sourceFiles){
    using (Stream stream = File.OpenRead(file))
    {
        using (Image sourceImage = Image.FromStream(stream, false, false))
        {
            Console.WriteLine(sourceImage.Width);
            Console.WriteLine(sourceImage.Height);
        }
    }}DateTime endDateTime = DateTime.Now;Console.WriteLine(string.Format(
    "Total duration [{0}] seconds. Total image count [{1}].", 
    (endDateTime - startDateTime).TotalSeconds, 
    sourceFiles.Length));

总持续时间[01855235]秒。总图像计数[33]。

这比原来的方法大约快250倍，原始方法：

DateTime startDateTime = DateTime.Now;string sourceFolder = @"C:\Temp";// Get all files from sourcefolder, including subfolders.string[] sourceFiles = Directory.GetFiles(sourceFolder, "*", SearchOption.AllDirectories);foreach (string file in sourceFiles){
    using (Image sourceImage = Image.FromFile(file))
    {
        Console.WriteLine(sourceImage.Width);
        Console.WriteLine(sourceImage.Height);
    }}DateTime endDateTime = DateTime.Now;Console.WriteLine(string.Format(
    "Total duration [{0}] seconds. Total image count [{1}].", 
    (endDateTime - startDateTime).TotalSeconds, 
    sourceFiles.Length));

总持续时间[474575263]秒。总图像计数[33]。