问System.OutOfMemoryException:内存不足

EN

public static int cookiecount;
public static Random random = new Random();
public static string[] files = Directory.GetFiles(Application.StartupPath, "*.png");
public static Image im;

public static void Draw(System.Drawing.Graphics g, int x, int y)
{
    try
    {
        im = Image.FromFile(files[random.Next(0, files.Count())]);

        g.DrawImage(im, x, y, 40, 40);
    }
    catch(Exception ee) {
        MessageBox.Show("Error! " +ee.Message + " " + ee.Source + " " + ee.HelpLink,
            "Oh No", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }

    cookiecount++;
}