4S when power on screen is enlarged

You may have the zoom control (settings>accessibility>zoom) turned on. When you wake up your phone with the home button, try this: double tap with three fingers and with all three fingers still touching the screen on the second tap, drag all three fingers down the screen. If the zoom function is turned on, this will zoom out to a normal view and you'll be fine.

Sorry, that should be; settings>general>accessibility>zoom