GUI Button + GUISkin = Bug, Help?

Hi, I am making a menu with gui.buttons and i have assigned them with a GUISkin. Here is my code:

public var MainMenuSkin : GUISkin; function OnGUI(){ GUI.skin = MainMenuSkin;

 if(GUI.Button(Rect(Screen.width/5.5,Screen.height/5.5,250,100), "PLAY")){
     Application.LoadLevel("MainScene");
 }
 if(GUI.Button(Rect(Screen.width/5.5, Screen.height/2.5,250,100), "HELP?")){
     Application.LoadLevel("Help");
 }
 if(GUI.Button(Rect(Screen.width/5.5, Screen.height/1.6,250,100), "OPTIONS")){
     Application.LoadLevel("Options");
 }

}

I have made a GUISkin and configured it to use a button picture I designed as the background, but when I run the game the texture looks wierd. The entire button is not getting the background. Here is a picture to show you: Normally the image Ive set as background for the buttons should cover the entire 250x100 GUI.Buttons.

Does anyone have any idea of why I am experiencing this?