Once upon a time, cash-strapped teenagers and 20-somethings who wanted their homes to reflect their personal style were limited to buying reproductions of famous photos, paintings and movie posters on websites like Allposters.com, or picking up generic prints from the likes of Ikea. Not exactly what you’d call art. But that has changed in recent years, as affordable e-commerce software and social media platforms like Instagram have given independent artists a way to sell their work directly to