This probably is not an accurate definition of vignette but I was taught years ago that a vignette painting is one in which a part of the painting comes within an inch of each edge of the paper or canvas. Anyway the edges of the painting, whether a vignette or not, are important. Early on I would regularly do a painting and then realize I did not not consider the edges and then fill them in with something. I was told once in a workshop that if you have 2” along the edge of the painting and it does not relate to the rest of the painting then you have a problem. Seems I just could not learn. Once I showed a fine artist friend in Santa Fe one of my paintings and ask her to critique it. She said just cut off 2” of one side of the painting and it would be fine. That just irritated me that I still could not see it. I cut off the edge and sold it. If the edges are considered first at the beginning of a painting things go a lot easier for us. It is good to be edgy.