iHandy Level Free

One of the tools from the excellent iHandy Carpenter toolkit app, iHandy Level Free turns your iPhone into a spirit level. By default, it will show just how wonky your device's accelerometer is, but tap the calibrate button and you get an accurate and great-looking level.Through this iphone app,you could manually adjust picture on the wall,put the i handy level on the top,and then recreate the orientation on other pictures.You just want to know if the picture is truly straight until you use a real level tool...