Photoreal humans, characters, product shots. Best for hero imagery, moodboards, thumbnails. Nano Banana specifically WINS at editing an image you upload — 'remove background', 'put this shirt on that person', 'make it night'.
DALL·E for anything with text (menus, posters, book covers). Canva AI for finished, designed assets — Insta carousels, ads, pitch slides, resumes. Both bake typography in so you don't fight fonts.