I too would cut so that the picture was straight. I am finding, more and more, that I actually do not want a perfect straight of grain. Often it frays more because I think fabrics are not as tightly woven as they used to be. I had one top that I sashed with a black Kona cotton. I learned to cut slightly off grain because otherwise I could pull a loose thread and it would be as long as the whole width of the fabric. And boy did that fabric like to fray!!!