This picture taken by my daughter a few years ago makes two important points. Watch your shadow and avoid getting it on the stone. Of course, photo editing software can help in getting rid of the shadow, but that may take more time than avoiding it in the first place and you don’t want your photo to look “doctored.”
And watch the feet. There are toes in the bottom of this picture. Those are easily cropped out.
Of course, if your children are involved enough in genealogy to help with picture taking–don’t get too concerned about a few feet and shadows. Be glad they’re helping you to do something and one day their feet will be much larger than they are in these pictures.