Black goes with pretty much everything. I don't see a problem with going with a black metal railing.

change everything... for a noticable change.

It was probably orginally white. You don't like white? That's what you would expect on a colonial house. If the base color of the house stays the same the garage door would look better white. The dark color emphasizes it and in general no one really wants to call attention to their garage. The shutters could be any dark color if you're tired of the green - black, charcoal, blue. It's a pretty house, and classic - I hope you don't want to make it look like Modern Farmhouse.

Black goes fine for the railing only in my opinion.

@kandrewspa Thanks. I'm not looking to make any big changes, and would prefer to keep everything the same as is. However, since we need to change the railing it was suggested that we go black.

That is a railing that would look so much better in white to match the trim of the house not the shutters.

White so you do not have to change anything else.