public class PictureAccessor
{
//Private field not necessary for Proxy pattern but required in order to get the loaded image name in the console application.
private static string _imageName;

//Define the IPicture interface represents the "blueprint" for a set of complex classes (objects).
public interface IPicture
{
Image GetImage();
}

//The LoadPicture class (object) inherits from the IPicture interface and represents one type of "complex" class.
private class LoadPicture : IPicture
{
public Image GetImage()
{
//Prepare extraction of the embeded image file
Assembly assembly = Assembly.GetExecutingAssembly();
string resourcePath = $"PatternsConsole.Structural.Proxy.Images.pictureloading.jpg";

using (Stream stream = assembly.GetManifestResourceStream(resourcePath))
{
if (stream != null)
{
_imageName = "pictureloading.jpg";
return new Bitmap(stream);
}
}

return null;
}
}

//The FinalPicture class (object) inherits from the IPicture interface and represents another type of "complex" class.
private class FinalPicture : IPicture
{
public Image GetImage()
{
//Prepare extraction of the embeded image file
Assembly assembly = Assembly.GetExecutingAssembly();
string resourcePath = $"PatternsConsole.Structural.Proxy.Images.picturefinal.jpg";

using (Stream stream = assembly.GetManifestResourceStream(resourcePath))
{
if (stream != null)
{
_imageName = "picturefinal.jpg";
return new Bitmap(stream);
}
}

return null;
}
}

//The PictureProxy class manages the creation of the "complex" classes and provides a single interface for the client.
public class PictureProxy : IPicture
{
//Public field not necessary for Proxy pattern but required in order to get the loaded image name in the console application.
public string ImageName;

private bool _loaded;
private bool _authenticated;
private IPicture _pic;
private Timer _timer;

public PictureProxy()
{
_loaded = false;
_authenticated = false;
_timer = new Timer(Timer_CallBack, this, 5000, 0);
}

public Image GetImage()
{
if (_authenticated)
{
if (_pic == null)
{
if (_loaded)
{
_pic = new FinalPicture();
}
else
{
_pic = new LoadPicture();
}
}

Image image = _pic.GetImage();
ImageName = _imageName;

return image;
}

return null;
}

public void Authenticate(string password)
{
if (password == "correctPassword")
{
_authenticated = true;
}
else
{
_authenticated = false;
}
}

private void Timer_CallBack(object obj)
{
_loaded = true;
_pic = null;
_timer.Dispose();
}
}
}