The first two pictures show the Union line in Brock Field, it faces the left of the picture. The Confederate advance came from the left of the picture, although some units flank the Union right which would put them on the far end of the field and curving around to the right of the picture.
These next two pictures were taken from a spot behind the Union line looking out just as they would have. The main Confederate advance would be coming directly at the viewer. In relation to the first two pictures these last two were taken on the right of the line. In picture #3 a monument can be seen just to the left of the farthest left man (Ray), that monument is the farthest right monument in the first two pictures, that should give you some idea of the relationship between the pictures.
Bull Run at Gettysburg: James McKay Rorty
3 days ago