As part of your reward, you can download Pottermore artwork of your Gryffindor common room as wallpapers and screensavers for your electronic devices in the following links.
wallpaper
pottermore
house cup
winner
gryffindor
common room
This Harry Potter wallpaper might contain
drawing room, withdrawing room, drawing room, living room, living room, sitting room, front room, parlor, and parlour.