Is this appropriate for a wedding guest dress?

I’ve never really been to a western wedding. Are these ok to wear? I don’t want to be offensive in any way… it’s a tight dress, is that ok? Sorry if that’s a stupid question! But I’m genuinely that unaware…

EDIT** so just to add, it is black tie and a formal wedding. And from what I gather the black one looks too see through. I’ll look for more options, I have these two dresses and will find somewhere else to wear them. Worst case scenario, I’ll wear the maroon.