The picture hanging strips by Command are wonderful to hang pictures. No hammer & nails. No holes in the wall. No crooked lines, no paint pulled off of walls. Target,WalMart, Lowes, and Meijers carry them.
The absolute easiest way to arrange a gallery wall without making nail holes, um, everywhere? Trace each frame onto butcher paper, mark the tightened wire height or hook position, then stick them to the wall with painter’s tape.