You can never go wrong with a classic white fire surround. Goes with everything.

I would paint the surround either black or a very dark navy blue black which will pick out the darkest tones in the wallpaper. The problem if you paint it white is it will then make the cream insert look dirty and more yellow. I wouldn’t worry about your picture frames until you have done all the main decorating and see how they look then. Love the marble paper btw

I agree with Chloe. White to me is such an obvious choice. We shouldn’t be afraid to pair with unfamiliar colours. I personally would have kept the mahogany, but with the white marble inset, it just would stand out like a sore thumb against the darker muted colours. Sand it down maybe? Hmmm!? Ok I’m thinking blues, greyish blue, picking up from the painting. So….I would be resigned to colour block the whole chimney breast & wooden surround….ouch!!! Sorry Mahogany 😅. As mentioned above, only once the chimney breast & surround is complete, can a decision be made on the picture frame. This could be same colour as chimney breast which can be spray painted to match, or perhaps a gold or brass frame would also work, given the colours picked up from the painting. The gold or brass display ornaments would continue to work well on the mantle and perhaps at the foot of the fireplace? Just a thought😉. These are just colour inspirations …

I kind of agree with the ‘White’ comment at the top but not if it’s a standard pure brilliant white. I actually thought the commenter meant use the white in the wallpaper and get a colour match, if possible.
I tend to be a bit more bold so would have gone with the darker colour in the paper and had a colour matched to that but opted for a shade darker