STYLETHREAD -- LET'S TALK SHOP!

i'm posting this here b/c i think it's more of a style than wedding question, but feel free to move it to the weddings sections ...

my sister is getting married sept 10th.  we're in ct so although it's after labor day, it is usually still summer weather here.  the ceremony is outside and reception is in a garden setting.  this is her dress:

or

i picked up these last night as the bridesmaid dresses:

  (from ann taylor loft) this dress is incredibly flattering and much cuter in person, i'm just having second thoughts about it.  will this look okay, or should i go with something else?