It is offering more than 300 items online.
The shop offers paintings, original prints, posters, books and catalogues with many of the works under £500.
David Messum said: “This won’t replace our shops but it will run alongside it. When we sell catalogues for a specific exhibition around a third of the artworks are sold unseen beforehand so we know people are willing to buy from a page or from a website.”
The site will also host a curated section focused on a specific themes or artists.
Works currently for sale include a collection of paintings and drawings by Norman Neasom such as this bar scene.