How to let it run orderly.

I have the program, code as follows,

if(e.getSource() == btn1)//if button1 is press
{
	btn1.setVisible(false);//do 1st (button become invisible)				
	imageLabel6.setVisible(true);//(image become visible)
	imageLabel7.setVisible(true);//(image become visible)

	try//do second(wait for 3 second)
	{
		Thread.sleep(3000);//wait for 3sec
	} catch (InterruptedException e1) 
	{
		// TODO Auto-generated catch block
	e1.printStackTrace();
	}
imageLabel7.setIcon(new ImageIcon("D:\\School Stuff\\Year3\\Sem2\\Object O Programming\\eCard\\Citizen.jpg"));
imageLabel6.setIcon(new ImageIcon("D:\\School Stuff\\Year3\\Sem2\\Object O Programming\\eCard\\CitizenOpp.jpg"));
}//do last (image changed after 3 second)

the problem now is that when i pressed the button, it will wait for 3second 1st, then the image will changed after 3 second.