How could I add ui images to an instantiated prefab by photon ??

I am working on an Android multiplayer game based on photon networking services .. In game after joining or creating a room, Player prefab get instantiated to the scene. In player controller script, I mentioned the Joystick move control that contains two ui images if i add the canvas prefab to the player root prefab, I will have two players joysticks in the scene so no one of us two can control his player. If I mention the joystick in the script then I drag the ui images to the prefab script components .. it will say missing image after hitting play, And I cant do the Find() method because its made to game objects not ui components pls a solution!!