Well there are so many things wrong with this, first not many picture frames have key hole slots, second not many frames would be secure on the gauge of nail used as they wouldn’t be long enough unless in plaster board, third, it would have been just as easy to measure the width between the centre of slots on frame, then put your spirit level up and mark with pencil where fixings are to go, the same for every picture hanging, choose the point and fix accordingly. Music was good!