I don't do a booking without a chat on the phone. You can tell a lot, and it weeds out those who want to avoid a call to begin with. Pics I think are a non-starter both ways.
As said above, if you have any sort of restrictions, you need to make them clear on all your advertising. You need to state plainly that you don't see e.g. men from Norway. And then if someone phones you up with a Norwegian accent, you need to be prepared to ask an awkward question - 'I was just wondering, are you from Norway?' If they say yes, then you can say, 'Well, I'm sorry, but AS I SAY CLEARLY ON MY PROFILE I don't see men from Norway.'
Just bear in mind that >80 percent of men won't read your profile, so you can write as much/whatever you want, but don't think this means anyone who doesn't met your criteria will avoid contacting you.