I love how to extended it and kept the colors, I love that red of curtain, blue of wall and ochre of chair and wooden
part of wall.
But there are some mistakes in extracting character from scan. (I can see white pixels on the lower part of chair where there's glow and some other here and there). Easy fix use inner glow blending option on extracted layer and use a dark color matching the line and play with opacity/fill and blending modes.
And I do think you would've used some texture on the BG too, because the scan part has that slight texture and BG is kinda crispy. And the lower right part of wall needs bit more dark. And since there is some glow on scan part, the BG part looks plain against is creating a disturbing contrast. I would add some glowy particles floating around in BG too. And the since the paintings are framed they can use some glass light reflection of the light coming from butterflies and candles. Since the painting looks kinda out of place since frame is being illuminated by light.
Overall, nice wall, I loved the colors! :D