If it is staged they must have checked the weather report for 4 Aug, as it was 88-90F with no precip in nearby Frederick. It would be 3-5F cooler on Catoctin Mtn (where Camp David is located). The grass and trees would be green as shown and short sleeves would be appropriate for the area. As for shadows that would depend on time of day. If he golfed in the AM and helo'd to Camp David, he should have had plenty of time to shoot skeet in the afternoon with plenty of sun until 5PM when the canopy up there should be casting some good shadows. The winds were 6 - 20mph (gusts) and hard to tell if his hair is mussed up (where is Michelle when you need her?), but that could play havoc with the porting visual (?). If this is a hurried photoshop, they couldn't recreate the scene in the last week or so as we have had near continuous snow on the ground with brown grass and no leaves on trees lately. That leaves the state of the shotgun, which already has been addressed.
Suggest we ask for a second photo, same season, perhaps with Michelle in the picture.