We initially hung a line in Dori's room - using metal picture-hanging wire attached at both ends with cute hooks (we bought ours at Target). We hug the art with butterfly office-binder clips - we found some in pinks and purples. If the art didn't fit on the line, it didn't go up in the house. That way she had some control over it.
Not all magnets will work on this paint. They have to be pretty strong magnets. You can try these pushpin magnets, rare earth magnets, or neodymium magnets. Some of our pictures just won't stick on the walls - the pictures on thicker paper.
My next project is to get some a few frames to put a few select pieces of artwork in. That will be the rotating gallery and we'll only have limited spot available for that.