It can, sometimes, be completely innocent.
I work in a male dominated industry, so most of my workmates are men.
I've worked for this company for 3 years, but came as part of an acquisition (so a lot of us joined at once 3 years ago, having worked together for a couple of years before that).
I'm friends with several of the guys from the old company (that was acquired), we sometimes send each other photos of things in our lives (interesting food, our same-age kids in school plays, our pet wearing a hat, the view from holiday, our christmas trees, just the stupid stuff we'd send to our same sex friends).
I don't know their wives and they don't know my DH, but I believe we'd be totally open to meeting each other's family if the occasion arose.
I once bought one of them some specialist food that I know they like as I buying some for myself, I sent another one a book DD had enjoyed for their DD.
I can honestly say there's been no flirting or hidden agenda in these interactions. They're literally just my workmates and could just as well be female.
I understand though, that as the woman in question here is new, they don't have the shared work history that I have with these guys.
But all in all, not everything is a smoking gun.