How do I make my buttons all the same size? - javafx

Question

Sorry, I have just begun learning javaFX and cannot figure out how to get all of my icons on buttons the same size. I tried a couple things but could not get it working, all help is appreciated. Thank you!
Wont let me post my question unless I add more details but I cant think of anything else to put so just ignore this whole paragraph as I ramble on so I can post my question and continue coding my game.
public class Main extends Application {
Stage window;
Button button;
Scene scene1, scene2;
public static final int ROCK = 0;
public static final int PAPER = 1;
public static final int SCISSORS = 2;
public static int userChoice;
public static void main(String [] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception
{
window = primaryStage;
//Layout 1
VBox layout = new VBox(20);
Label label = new Label("Rock Paper Scissors");
Button myButton = new Button("Start");
myButton.setOnAction(e -> window.setScene(scene2));
Button exit = new Button("Exit");
exit.setOnAction(e -> System.exit(0));
layout.getChildren().addAll(label, myButton, exit);
layout.setAlignment(Pos.CENTER);
scene1 = new Scene(layout, 300, 300);
//Layout 2
BorderPane border = new BorderPane();
VBox layout1 = new VBox(10);
Label label1 = new Label("Choose One");
layout1.setAlignment(Pos.CENTER);
//Layout 3
HBox layout2 = new HBox(10);
//Rock Image Button
Image rockIm = new Image(getClass().getResourceAsStream("Rock2.png"));
Button rock = new Button();
rock.setGraphic(new ImageView(rockIm));
rock.setOnAction(e -> userChoice = ROCK);
//Paper Image Button
Image paperIm = new
Image(getClass().getResourceAsStream("Paper2.png"));
Button paper = new Button();
paper.setGraphic(new ImageView(paperIm));
paper.setOnAction(e -> userChoice = PAPER);
//Scissor Image Button
Image scissorIm = new
Image(getClass().getResourceAsStream("Scissor2.png"));
Button scissors = new Button();
scissors.setGraphic(new ImageView(scissorIm));
scissors.setOnAction(e -> userChoice = SCISSORS);
Button quit = new Button("Return");
quit.setOnAction(e -> window.setScene(scene1));
layout2.getChildren().addAll(rock, paper, scissors, quit);
layout2.setAlignment(Pos.CENTER);
scene2 = new Scene(layout2, 300, 300);
window.setTitle("Rock Paper Scissors");
window.setScene(scene1);
window.show();
}
}