Winslow Homer’s high drama arrives in Britain, an anticolonial hero takes his rightful place on the fourth plinth and some new Warholia surfaces – all in your weekly dispatch
She’s only 29 yet her paintings have already been scooped up by the Tate and fetched over £1m at auction. Now she’s thinking even bigger. On the eve of a new exhibition, the artist talks colour visions and anime obsessions