位图未处理？

Question

我有一个简单的循环，可以使用CopyFromScreen创建位图：

static void Main(string[] args)
    {
        while(true)
        {
            Bitmap bitmap = new Bitmap(makeScreenshot());
            Thread.Sleep(1000);

            bitmap.Dispose();

        }            
    }

    public static Bitmap makeScreenshot()
    {
        Bitmap screenshot = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb);

        Graphics gfxScreenshot = Graphics.FromImage(screenshot);

        gfxScreenshot.CopyFromScreen(Screen.PrimaryScreen.Bounds.X, Screen.PrimaryScreen.Bounds.Y, 0, 0, Screen.PrimaryScreen.Bounds.Size, CopyPixelOperation.SourceCopy);

        gfxScreenshot.Dispose();

        return screenshot;
    }

但是我可以看到每个循环在内存中的增加？如果我将新的位图修改为此：

Bitmap bitmap = new Bitmap(1024,768);

处置似乎按预期方式工作，那么makeScreenshot是否以某种方式保存对象？

谢谢