Definitely harassment - I feel sorry for the guy, he's obviously sexually frustrated, a nerd and doesn't know how to talk/relate to women properly. he's probably into video games cos he's socially awkward, but he's still a guy so you get this sort of behaviour over the internet.
i also do feel bad for the girl, guys don't pull this shit with other guys, cos they'll get smacked, but with women, it's a different thing, they're the alpha, bossman and they feel in their element.
It's basically most dudes alive - and not knowing responsible behaviour towards girls you like is very common these days. Not many dads teaching their sons like in the previous generations, hell, not many dads about , and most single moms too busy trying to do the work of two parents - meanwhile their sons get drawn to other males and pick up the same problematic behaviour they exhibit.
I do wonder why she kept responding though? Surely she could have blocked him or just ignored him if she didn't want it, and how did she manage to catch a calling snapshot if she wasn't actually setting him up and exploiting his vulnerability (yeh, male vulnerability is this kind)? Then sharing it o make him pay (well this is how girls can get back at guys) although sometimes I think their retribution doesn't match the crime, - it's a definitely a girl version of "don't fuck with me or i'll finish you"