Depends on the wedding, if you know the bride is wearing a long dress and the bridesmaids have full length or waisted full skirted colourful satin outfits, then I can't see a problem.
I've been to two very informal, bride in ordinary summer clothes weddings where that might have been a problem.
Except neither bride would have given a flying fuck. If they had cared about that sort of stuff they wouldn't have been in cotton dresses less showy than most of their guests.
(Certainly less showy, in the second case, than me and the DDs as we had outfits to use for a mor formal wedding later that summer)