What time is the wedding? Inside or outside?
You are totally on the right track with either dress for black tie optional, but the time/location could help narrow down your chocies in make-up,shoes and accessories. If we are voting, I like the second dress for the color/style, but choose what best flatters your body shape.
If the bride herself is doing a fancy fascinator in her hair instead of a veil (what denomination is this wedding? Maybe that could help give clues?) I wouldn't want to "compete" with her by wearing a fancy one too. Are you close enough to the bride that you could just ask?
But on the other hand, if it is popular where you are for weddings, why not wear a simple one? It could be a nice ice breaker when socializing later! Wedding fashions from abroad!
A.
