She stood beside her brother for the picture.
Besides having some serious side effects, the medication was also expired.
He didn't know what to do besides put up the posters.
It can be both. Examples:Jim leaned his can beside his chair.Beside the front door sat an ornate lion statue.Jill was beside herself with worry.Besides Mary, Tom and Gina attended the...
I don't think you're allowed to do that, besides, miss is watching.