How to Prompt for App and UI Icons - Nano Banana 2

Recognition at small sizes comes almost entirely from outline. Before writing anything, decide what shape the icon makes as a solid black blob — if that blob is ambiguous, no amount of interior detail will rescue it. So the prompt should lead with the silhouette and treat everything else as secondary: a single bold shape, high contrast against the background, generous internal spacing.

That means actively suppressing the things the model wants to add. Ask for flat colour with no gradient, no drop shadow, no reflection, no thin lines, and a shape that fills the frame rather than floating small in the middle. Left alone, models produce the glossy, bevelled, softly-lit object that dominated icon design fifteen years ago, and that treatment is exactly what dissolves when downscaled.

Say which kind of icon you mean, too, because the conventions differ sharply. An app tile is a full-bleed square with a background and lives on a home screen. An interface glyph is a bare mark with no container that must sit comfortably beside text. Prompting for one and using it as the other is a common and very visible mistake.

Icons almost never ship alone, and a set that does not share a visual language looks worse than any individual icon in it. Fix the style description word for word, change only the subject, and generate the whole set in one pass so nothing drifts. If your generator supports it, keeping the same seed across the set helps hold weight and proportion steady.