Google switched Imagen 4 off today — and its recommended replacement costs 68% more per image, in every tier

Google's Imagen 4 endpoints — `imagen-4.0-generate-001`, `imagen-4.0-fast-generate-001` and `imagen-4.0-ultra-generate-001` — were shut down on the Gemini API on 17 August 2026. On Vertex AI the same models had already gone dark on 30 June. Today's date closes the fourth and final generation of Google's dedicated text-to-image line: there is no Imagen 5, because image generation now happens inside Gemini through the ordinary content call. The migration note on Google's Imagen page names one successor: Gemini 3.1 Flash Image, sold under the name Nano Banana 2. Put that recommendation next to Google's own price list and a consistent pattern appears. Imagen 4 Standard cost 4.0 cents an image; a 1K image from Gemini 3.1 Flash Image costs 6.7 cents — 68% more. Imagen 4 Ultra, which rendered up to 2K, cost 6.0 cents; a 2K image from the replacement costs 10.1 cents — again 68% more. Imagen 4 Fast, the cheapest first-party image Google ever sold at 2.0 cents, has no equal at all in the Flash Image list: the nearest floor is Gemini 3.1 Flash Lite Image at 3.36 cents for a 1K image, which is — for the third time — 68% more. Two details do not show up in a per-image comparison. The first works against the migration: Imagen billed nothing but the finished image, while the Gemini image models charge separately for what goes in, at 0.50 dollars per million input tokens for Flash Image and 0.25 for Flash Lite Image. A long prompt or a reference photograph therefore adds cost that the old model did not meter at all. The second works in its favour: the batch tier of Gemini 3.1 Flash Image costs 3.4 cents for a 1K image, which is genuinely below the old Imagen 4 Standard price. Anyone whose images do not have to appear within seconds can migrate and pay less than before — the 68% premium is the price of doing the same work in real time. For the catalogue the shutdown means one more entry in a pattern we track model by model: a product line withdrawn not because a better version of it arrived, but because the capability moved into a general-purpose model, and the meter moved with it.