This is a submission for the Google I/O 2026 Writing Challenge
Google now has six image models (one is called "Nano Banana"). Here's which to actually use.
Everyone covering Google I/O 2026 is writing about agents, Antigravity, and whether AI is coming for our jobs. Meanwhile, I opened AI Studio, clicked into image generation, and found a quietly hilarious situation: six different image models, two completely different families, prices ranging nearly 7×, and one of them is officially named "Nano Banana."
Nobody's written the guide for this. So here it is — the two families, what each is for, and the price-vs-quality call, in plain terms.
💡 [Screenshot spot: the AI Studio model picker filtered to image models, showing Nano Banana / Nano Banana Pro / Imagen 4 stacked. Or even better — a single image you generated, with the prompt shown.]
Two families, two totally different jobs
This is the part the model names actively hide. Google has two separate lines of image models, and they're built for different things:
Family 1 — Imagen 4 (the dedicated text-to-image line). You give it a prompt, it gives you a picture. Pure generation, no conversation. It's the cheapest and fastest path to "make me an image."
| Model | Price per image |
|---|---|
| Imagen 4 Fast | $0.02 |
| Imagen 4 | $0.04 |
| Imagen 4 Ultra | $0.06 |
Family 2 — "Nano Banana" / Gemini Image (the conversational line). These are Gemini models with image generation built in. You don't just prompt them — you talk to them. "Make the sky orange." "Now remove the car." "Keep everything but change the text on the sign." They reason about the image and edit it in context, because they're full multimodal models under the hood.
| Model (a.k.a.) | Real ID | Price per image |
|---|---|---|
| Nano Banana (Gemini 2.5 Flash Image) | gemini-2.5-flash-image |
$0.039 |
| Nano Banana 2 (Gemini 3.1 Flash Image) | gemini-3.1-flash-image-preview |
$0.0672 |
| Nano Banana Pro (Gemini 3 Pro Image) | gemini-3-pro-image-preview |
$0.134 |
(Yes, "Nano Banana" is the real product nickname. Yes, "Nano Banana Pro" uses a Gemini 3 Pro backbone while "Nano Banana 2" uses Gemini 3.1 Flash — so the "2" is newer than the "Pro." The naming is a maze. The capabilities are what matter.)
The 7× spread, and why it exists
Imagen 4 Fast is $0.02 an image. Nano Banana Pro is $0.134 — about 6.7× more. That's not a rip-off; you're paying for two different things:
- The cheap Imagen models are generators. One prompt, one image, done. Brilliant for volume — product mockups, thumbnails, social assets, anything where you'll generate hundreds and pick the best.
- The pricier Nano Banana models are editors and reasoners. They hold the image in context and let you iterate conversationally, preserve details across edits, and ground the result in reality (text that's actually spelled right, hands with five fingers). You pay more because you're getting an image collaborator, not a vending machine.
Which one should you use?
The decision guide AI Studio doesn't give you:
Reach for Imagen 4 (Fast / standard / Ultra) when:
- You need lots of images cheaply, from a prompt, with no editing loop.
- Use Fast ($0.02) for drafts and high volume, standard ($0.04) for most production, Ultra ($0.06) when you need the best single-shot quality.
- Think: marketing assets, blog headers, product variations, anything batch.
Reach for Nano Banana / Gemini Image when:
- You need to edit iteratively — "change this, keep that" — or have a conversation about the image.
- You need reliable text-in-image, precise edits, or reality-grounded detail.
- Use Nano Banana 2 ($0.067) as the balanced default; step up to Nano Banana Pro ($0.134) only when you need top-tier editing fidelity and it's worth ~2×.
- Think: design iteration, image editing tools, anything where the first output is the start of a conversation.
The rule of thumb: generating → Imagen. Editing or iterating → Nano Banana. Most people will default to whatever's at the top of the dropdown and overpay (or underpower) without realizing there were two different tools.
A couple of gotchas worth knowing
- Per-image pricing is separate from text pricing. The Nano Banana models also charge for the text tokens in your prompt/conversation (e.g., Nano Banana 2 is $0.50 in / $3.00 out per million text tokens, plus $0.0672 per image). Imagen is effectively just the per-image cost. For chatty editing sessions, those text tokens add up.
- "Preview" means impermanent. Nano Banana 2 and Pro are both preview models. Great for building now, but don't hard-code a preview model ID into something you can't easily change later.
- Newer ≠ higher number. Nano Banana 2 (Flash, Feb 2026) is newer than Nano Banana Pro (Pro backbone, Nov 2025). Pick by the backbone and job, not the suffix.
The takeaway
While the rest of the internet argues about whether agents will replace developers, Google quietly shipped a six-model image stack split across two philosophies — generate fast and cheap (Imagen) versus edit and reason (Nano Banana) — with a 7× price spread and names that tell you almost nothing.
The five-second version: if you're producing images, start with Imagen 4. If you're editing them, reach for Nano Banana. Match the tool to the verb, and you'll get better images for less money than whoever just clicked the first option.
Open AI Studio, generate the same prompt on Imagen 4 Fast and on Nano Banana 2, and look at the difference for yourself. Five minutes, and the dropdown stops being a mystery.
Model names, IDs, and per-image prices are from Google AI Studio's model picker during the I/O 2026 window; verify current pricing on the official Gemini API pricing page before relying on it, as preview models and prices change. I drafted this post with AI assistance and verified the details against AI Studio myself — the analysis and any generated images are mine.
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