title: blitting moving images in pygame
body: <p>First time making something in pygame...
  I i'm trying to generate several instances of an image and then scroll them bottom to top. For some reason the original imagestays put while the other imagemove as expected. I am also trying to generate instances of the image on the leftmost quarter of the screen or the rightmost quarter. My images only show up on the left. My gameDisplay is 1150x500 pixels.
  Any tips on how i can correct my code would be greatly appreciated!</p>
  
  <p>here's the method i'm using:</p>
  
  <pre><code>def gameHighScore():  
      points=0
      guesses=0
      time=0
  
      balloons= pygame.image.load("balloons.png") 
  
      objects=[]
  
      for i in range (4):
          xpos= random.randrange(0, round(display_width/4)) or random.randrange(round((3/4)*display_width), display_width)
          #object generated at start height 400, random xpos with a speed -i*2
          o=Balloons(balloons, 400, xpos ,-i*2)           
          objects.append(o) 
  
  
      gamehs=True
      while gamehs:
          for event in pygame.event.get():
              if event.type==pygame.QUIT:
                  pygame.quit()
                  quit()
              if event.type==pygame.KEYDOWN:
                  if event.key==pygame.K_SPACE:   # space for continue
                      paused=False
                      gameTimer.start()
                  elif event.key==pygame.K_q: #q for quit
                      pygame.quit()
                      quit()
  
  
  
          for o in objects:
              gameDisplay.fill(BLACK)
              message_to_screen("HIGH SCORE", WHITE, y_displace=-100, size="large")
              message_to_screen(" You scored " +str(points) +" points", WHITE, y_displace=0, size="medium")
              message_to_screen("in " +str(time) +" after " +str(guesses) +" guesses", WHITE, y_displace=50, size="medium")
              button("Play (space bar)", 300,400,250,50, GRAY, BLUE, action ="continue")
              button("Quit (Q)", 600,400,250,50, GRAY, BLUE, action ="quit")
          for o in objects:
              o.move()
              gameDisplay.blit(o.image, o.pos)
  
  
          pygame.display.update()
          clock.tick(30)              #static screen, no need for high fps
  </code></pre>
  
  <p>And here's the class that moves objects:</p>
  
  <pre><code>class Balloons:
  
      def __init__(self, image, height, xpos, speed):
          self.speed=speed
          self.image=image
          self.xpos=xpos
          self.pos=image.get_rect().move(xpos, height)             #momve(x,y) change x to random
  
      def move(self):
          self.pos=self.pos.move(0, self.speed)
          if self.pos.top&lt; -200:
              self.pos.bottom=800
  </code></pre>