MY CODE >> Simple Screen Scrolling
-- Tommy Martin
-- 8/27/2014
-- Simple Screen Scrolling
-- Press arrows to move to different places on the screen

-- housekeeping stuff

display.setStatusBar(display.HiddenStatusBar)

local centerX = display.contentCenterX
local centerY = display.contentCenterY
local right = display.contentWidth
local bottom = display.contentHeight

-- set up forward references

local background
local moveBackground
local currentX = centerX
local currentY = centerY

-- create play screen

local function createPlayScreen ()
 
  -- background
  
  background = display.newImage("background.png")
  background.xScale = 10
  background.yScale = 10
  background.x = currentX
  background.y = currentY

  -- buttons
  
  local upArrow = display.newImage("arrow.png")
  upArrow.x = centerX
  upArrow.y = 90
  upArrow.alpha = .7
  upArrow:addEventListener ( "tap", function() moveBackground(0, 200) end )

  local downArrow = display.newImage("arrow.png")
  downArrow.x = centerX
  downArrow.y = bottom - 90
  downArrow.alpha = .7
  downArrow:rotate(180)
  downArrow:addEventListener ( "tap", function() moveBackground(0, -200) end )

  local leftArrow = display.newImage("arrow.png")
  leftArrow.x = 90
  leftArrow.y = centerY
  leftArrow.alpha = .7
  leftArrow:rotate(270)
  leftArrow:addEventListener ( "tap", function() moveBackground(200, 0) end )

  local rightArrow = display.newImage("arrow.png")
  rightArrow.x = right - 90
  rightArrow.y = centerY
  rightArrow.alpha = .7
  rightArrow:rotate(90)
  rightArrow:addEventListener ( "tap", function() moveBackground(-200, 0) end )

end

function moveBackground (xVal, yVal)
	currentX = currentX + xVal
	currentY = currentY + yVal
	transition.to (background, { x = currentX, y = currentY, time = 300 } )
end

createPlayScreen()