I think he has the bag at his feet in the “no bag” photo.
I think the “no bag” photo is actually earlier in time than the “bag” photo.
In the “no bag” photo, the two men are about 100 feet away from the bomb site. There is a large crowd. The big photo scene which includes these two men shows a race time of 2:35. This was still while elite runners were crossing the line, accounting for the much larger crowd.
In the “bag” photo, the two men are in a different spot, much closer to the bomb site - just several feet away. The crowd is much thinner, so this is probably later on and closer in time to the 4:09 explosion time.
Thanks for your interesting comments and details about those photos (noting time stamps, etc.). I hadn’t noticed the race times...