re: disappointment – cosmetics are allowed & encouraged, won’t they lead to a future disappointment?
so, just need to make sure that disappointment does not happen before people learn more about each other, as Syag says. Thus, the pictures should be as good as the cosmetics – and not better – to prevent early disappointment.
All I know about cosmetics is from Gemora, and it says that cosmetics are different according to income (even as we try to make some of it affordable to the poorest ladies by allowing peddling cosmetics). Thus, a Talmid Chacham can see pictures and presume that cosmetics is of the same quality (see above) and thus make judgement – how long the shver will be able to support the learner.