Nano Banana vs ChatGPT Images in 2026

Key takeaways

• ChatGPT Images 2.5, released September 8, 2026, leads Arena's public text-to-image and image-editing leaderboards, where people vote between anonymous outputs.

• Google's Nano Banana 2.1, released October 6, 2026, is the stronger pick for consistent characters and products, with up to 14 reference images, and for very wide or tall formats up to 8:1.

• Both are free to try with limits that neither company publishes as a fixed number. Gemini's free downloads are capped at 1K, and ChatGPT's images with thinking need a Plus plan.

• In the API, Nano Banana 2.1 costs about $0.034 for a 1K image. OpenAI charges by tokens, and on its GPT Image 2 figures a medium-quality square image costs about $0.053, so Nano Banana is cheaper at every setting except ChatGPT's lowest.

• Both now carry Google's SynthID watermark and C2PA metadata. Only Gemini adds a visible watermark, and since August 2026 you can turn it off.

Which models are we comparing?

"Nano Banana" is Google's name for its Gemini image models. The original Nano Banana (Gemini 2.5 Flash Image) arrived in August 2025, Nano Banana Pro followed in November 2025, and Nano Banana 2 became the default in the Gemini app in February 2026. Nano Banana 2.1, released October 6, 2026, is the newest, and it's rolling out to the Gemini app, AI Mode in Search, Flow and Google AI Studio. Nano Banana Pro is still available on paid Gemini plans through "Redo with Pro."

ChatGPT's image generation runs on OpenAI's GPT Image models. ChatGPT Images 2.0 launched in April 2026, and ChatGPT Images 2.5 replaced it on September 8, 2026, on every plan, Free included. In the API, 2.5 comes in two versions: Flare, which is faster and is what ChatGPT uses by default, and Sunburst, which is slower and more precise.

Nano Banana vs ChatGPT Images at a glance

Image quality

On Arena's text-to-image leaderboard in early October 2026, OpenAI's two Images 2.5 models hold the top two places and the older GPT Image 2 is third. Nano Banana 2.1 entered at fifth on its first day, ahead of Nano Banana 2 and Nano Banana Pro. Its score is still provisional, so expect its place to move over the next few weeks.

Decrypt's head-to-head was closer than the leaderboard suggests. Its comparison of Images 2.5 against Nano Banana 2 in September ended in a 3-3 draw: Nano Banana won on realism, dense lettering and a research-based timeline, while ChatGPT won on spatial layout, illustration and abstract ideas. The Decoder found that Nano Banana 2.1 beats Pro on Google's own preference scores, but that Pro often still produces better color and proportions.

Text in images

ChatGPT made the jump with Images 2.0, which added dense and multilingual text, and its thinking mode can search the web before it generates an image. Nano Banana 2.1 can ground an image in Google Search, which helps with charts, timelines and anything that depends on real dates or figures. In Decrypt's test, ChatGPT got a year wrong in a timeline and made small text errors that Nano Banana avoided, so check the details on either before you publish.

Editing

ChatGPT is ahead here. Images 2.5 leads Arena's image-editing leaderboard, and OpenAI says it's better than 2.0 at keeping the subject of a reference photo and at following edits across several turns. You can select part of an image and describe a change, leave comments directly on the image, or sketch a rough layout and have ChatGPT render it.

Nano Banana edits through conversation in the Gemini app, and 2.1 adds mask-based editing for changing one area without touching the rest. It's new, so there's little independent testing of it yet. Gemini requires you to be 18 or older to edit images, though 13 is the minimum to generate them.

Keeping characters consistent

This is Nano Banana's strongest area. Google publishes clear limits: 2.1 takes up to 14 reference images, with up to four characters and 10 objects, so you can keep the same person or product across a series of images. OpenAI's API accepts up to 16 input images for edits and says 2.5 is better at preserving subjects, but it doesn't publish a character figure.

Image size and shape

Nano Banana handles far more extreme shapes, from 8:1 banners to 1:8 vertical strips, while ChatGPT stops at 3:1. Both top out around 4K. For free users there's a practical gap: Gemini's free plan downloads at 1K and paid plans at 2K in the app, and 4K output is through the API.

What it costs

Neither company publishes a fixed free limit. Google now sets Gemini limits by compute rather than image count, refreshing every five hours up to a weekly cap, and paid plans multiply that allowance: AI Plus gives twice the free limit, AI Pro four times and AI Ultra more. Nano Banana Pro needs a paid Google AI plan.

On ChatGPT, Free and Go ($8 a month) get limited image creation, Plus ($20) adds images with thinking, and Pro (from $100) makes image creation unlimited, subject to abuse guardrails.

For developers, Nano Banana 2.1 costs $0.0336 for a 1K image, $0.0504 at 2K and $0.0756 at 4K, with batch jobs at half price. That's about half the price of Nano Banana 2, whose API version shuts down on October 29, 2026. OpenAI charges by tokens, $30 per million image output tokens on Images 2.5, and hasn't published per-image figures for it. On GPT Image 2, a 1024 x 1024 image cost about $0.006 at low quality, $0.053 at medium and $0.211 at high. Unless you only need ChatGPT's low setting, Nano Banana 2.1 is cheaper, even at 4K.

Watermarks

Since May 2026, both companies mark their images the same way under the hood. ChatGPT images now carry Google's SynthID invisible watermark as well as C2PA metadata, and Gemini images carry both too. Gemini also adds a small visible watermark, which you can switch off in Settings in most countries since August 2026 (work and school accounts can't).

What neither will make

Neither allows explicit images. OpenAI paused its planned adult mode for ChatGPT in March 2026, and even as planned it covered text, not images. Both bar sexual images of real people and impersonating someone's likeness without consent.

Which should you use?

• Photos and illustrations people will prefer at a glance: ChatGPT Images 2.5.

• Editing an image over several rounds: ChatGPT Images 2.5.

• The same character or product across a series: Nano Banana 2.1.

• Banners, panoramas and tall formats: Nano Banana 2.1.

• Infographics, timelines and dated facts: Nano Banana 2.1 with Search grounding, and check the text on either.

• High-volume API work: Nano Banana 2.1, unless ChatGPT's low-quality setting is good enough.

Frequently asked questions

Is Nano Banana better than ChatGPT for images?

For most people, ChatGPT Images 2.5: it leads public preference leaderboards and is the better editor. Nano Banana 2.1 is better at keeping characters consistent, supports wider formats and costs less in the API.

What is Nano Banana?

Nano Banana is Google's name for its Gemini image models. The newest is Nano Banana 2.1, released October 6, 2026, and Nano Banana Pro is still available on paid plans.

Which image model does ChatGPT use?

ChatGPT Images 2.5, released September 8, 2026. In the API it comes as GPT-Image-2.5 Flare and GPT-Image-2.5 Sunburst.

Are Nano Banana and ChatGPT image generation free?

Yes. Google caps free use by compute that refreshes every five hours, and OpenAI calls its free tier limited without giving a number. Free Gemini downloads stop at 1K, and images with thinking need ChatGPT Plus.

Do Nano Banana and ChatGPT images have watermarks?

Both embed SynthID and C2PA. Only Gemini shows a visible mark, and in most countries you can switch it off in Settings.