This is really my first actual program I made, it's pretty simple but amusing, the only this is I need to know how to get it to randomly choose between which message to display when a button is pressed then have the other button say the remaining choice, I also need it to show a specific image, depending on which message the random message generator chooses item the random message when a button is clicked, I keep getting the "Cannot implicitly convert type 'string' to 'System.Drawing.Image' " message, please help, the code is below if you want to mess around with it and let me know what you find.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
label2.Text = "Choose a door and read the message in the lagre box above, then hit clear and click the other door, read it's message.";
}

private void button1_Click(object sender, EventArgs e)
{
richTextBox1.Text = "Congratulations, you just won the game!";

private void button2_Click(object sender, EventArgs e)
{
richTextBox1.Text = "Sadly, you chose the wrong door, sending you spiraling down into eternity.";
}

private void button3_Click(object sender, EventArgs e)
{
richTextBox1.Text = " ";
}
}
}