After waiting for 3 weeks, the paintings came in this morning. We bought 3M tapes to mount the paintings, considering that we didn't want to damage the walls. The first time we tried it, the paintings stayed on the wall for like 3 minutes. Learning from that lesson, we went to the mart, bought double the amount of tape and tried putting up the paintings again. All was well, until we heard a loud "thud" and one of the paintings were on the ground. Seems like the adhesive goes well with the wall but not with the canvas. Third time, we stapled the tapes to the canvas, and then attached the tapes to the ones already attached to the wall. Touch wood, the paintings are still in tact.