Nano Banana 2.1 goes GA in the Gemini API at half Nano Banana 2's price, and the old model shuts Oct 29

Google's new image generation and editing model (gemini-nano-banana-2.1) shipped Oct 6 with better text rendering, up to 14 reference images, and Search grounding at $0.0336 per 1K image, $0.0504 at 2K, and $0.0756 at 4K, about half of Nano Banana 2, with batch halving that again. If your app calls gemini-3.1-flash-image, switch the model ID before it's shut down on Oct 29; there's no free API tier for 2.1.