I don’t see anything cradled in her left arm but I’m looking at a small image at the moment. I used to play some paintball/capture the flag and always used a hopper on top of the gun so I wasn’t refilling paintballs one at a time. No paintballer ever plays without a hopper and none of the guns, to my recollection, had either a scope-like attachment on the barrel or a gun butt. I haven’t played in awhile so it’s possible the designs have changed. I’m leaning towards it not being a paintball gun.
It’s probably airsoft as noted, and she has Smith optics safety glasses on (which are really good, I use them )