@Sviatogor i think that physical appearance of Slavic people varies. From South to the North etc.
South Slavs are mixture of different influences. But largely Slavs. If you look at Russia, they are full of non Slavic and even non European influences. I can agree with you that Belarus and Polish people are probably the most “old Slavic” look a like. But on the other hand, if you check pictures of Gorals, Hutsuls, Lemkos and other highlander people you can easily find cross references with average look of some Dalmatian guy or woman. Way of life and area where you live can easily change and shape a person, population in every way.