Image scaling in unity - complete beginner

Hello guys, I have a question about scaling images . I have problem that my images are not scaling, when choosing different resolution. I see that when i change to different resolution, my pictures position stays the same which for sure is not correct. My question is how to manage that? I really tried and nothing works. Here i attach screens from game so you can see. I will be happy for any answer.
Thanks!

and here it is after changing resolution

Texture2D t;
t=new Texture2D(1,1);

void OnGUI(){


			int x = Screen.width;
			int y = Screen.height;
	GUI.DrawTexture(new Rect(x*.25f,y*.25f,y*.5f,y*.5f),t);
       //image height and width will allways be half of screen height
}