help with jigsaw puzzle code

i am trying to get the screenshot to dissipear after it has been taken. does any one know what is wrong with my code? here it is

local function

captureDeviceScreen ( )

local captured_image = display.captureScreen ( true )

captured_image:scale (.5, .5)

local alert = native.showAlert ( “Success”, “Captured Image is Saved to Library”, { “OK” } )

end

Runtime:addEventListener(“tap”, captureDeviceScreen)