Bannister is primarily known for his idealized landscapes and seascapes, but he also executed portraits, as well as biblical, mythological, and genre scenes. He advertised himself as a portraitist as a young painter, but eventually became popular for his landscapes. An intellectual autodidact, his tastes in literature were typical of an educated Victorian painter, including Spenser, Virgil, Ruskin, and Tennyson, from whose works much of his iconography can be traced. Much like George Inness, his work reflected the composition, mood, and influences of French Barbizon painters Jean-Baptiste-Camille Corot, Jean-François Millet, and Charles-François Daubigny. Defending Millet in "The Artist and His Critics", Bannister saw him as the most "spiritual artist of our time" who voiced "the sad, uncomplaining life he saw about him — and with which he sympathized so deeply."