[JamesP81]

Still, why would a smoke puff and spent casing be photoshopped in, but no mag?

I don't know, but I'm also pretty sure the case is photoshopped. M4s tend to eject cartridges backwards past the shooter. This one, however, appears to be either even with or even a little in front of the ejection port.

As to why they'd photoshop it, maybe they are learning newer and better tricks. I don't know.

[SFC Chromey]

M4's tend to spit them out sideways when they have the brass deflector that is part of the weapon. On old M16's you had to insert a brass deflector, now you don't need one if you are a lefty.