GPT Image 2 appears to be the stronger benchmark leader, especially for prompt following, text-in-image, spatial reasoning, and edits, while Nano Banana is the better default when speed, cost, Gemini integration, and high-resolution/4K workflow matter more. The evidence is uneven: official docs confirm model availability/features, but many “benchmark” numbers come from third-party arenas or SEO-style comparison posts, so treat exact Elo gaps and category scores as directional rather than definitive.

Key benchmark takeaways

• GPT Image 2 is listed in OpenAI’s API docs as gpt-image-2-2026-04-21, confirming it is an API model with documented rate limits and access controls ^[1].

• Google’s official Nano Banana image-generation docs show support for multiple aspect ratios and selectable resolutions including 512, 1K, 2K, and 4K ^[2].

• Third-party benchmark reports generally rank GPT Image 2 above Nano Banana/Nano Banana 2 in overall image-generation quality, with one Arena-related report claiming GPT Image 2 reached about 1512 Elo and led Nano Banana 2 by 242 points in text-to-image ^[13].

• Artificial Analysis has a dedicated GPT Image 2 model page comparing quality, generation time, and price against other image models including Nano Banana, but the search result did not expose enough numeric details to independently verify all scores ^[11].

• A hands-on comparison found a much closer result: 2 GPT wins, 2 Nano Banana wins, and 2 ties, summarizing GPT as better when “every character matters” and Nano Banana as better when “every pixel of light matters” ^[9].

Comparison table

Dimension	GPT Image 2	Nano Banana / Nano Banana 2	Practical winner
Overall arena ranking	Reported as #1 in some third-party image arenas, with a claimed 1512 Elo and large lead over Nano Banana 2 [13]	Reported as #2 in the same comparison, around 1360 Elo in one source [13]	GPT Image 2, but verify live leaderboards
Text rendering	Multiple comparisons say GPT Image 2 leads on text accuracy and layout-heavy outputs [10][14]	Often described as improved but weaker for exact text and multi-constraint typography [9][14]	GPT Image 2
Prompt adherence	GPT Image 2 is repeatedly described as stronger on complex constraints, spatial logic, and multi-object instructions [10][14]	Nano Banana is competitive for simpler creative prompts and fast production tasks [9]	GPT Image 2
Photorealism / lighting	Hands-on comparison says Nano Banana wins where lighting and pixel-level aesthetics matter [9]	Nano Banana is often praised for realism, speed, and polished visuals [9]	Nano Banana, depending on prompt
Editing	Arena-related snippets say GPT Image 2 scored highly on single-image edit tasks [13]	Nano Banana is widely positioned as strong for editing and image-grounded workflows, but exact benchmark evidence is thinner in the available results [2][15]	Slight GPT Image 2 on benchmark claims; Nano Banana for workflow
Resolution	OpenAI pricing/docs confirm GPT Image 2 exists, but search snippets did not expose a complete official resolution matrix [1][3]	Google’s official docs show Nano Banana supports 512, 1K, 2K, and 4K outputs [2]	Nano Banana for explicit 4K support
Speed	Some comparison posts claim Nano Banana is faster and more production-efficient [9][14]	Official Google docs confirm generation API support but not benchmark speed in the search snippet [2]	Nano Banana, based on third-party reports
Cost	OpenAI’s pricing page lists GPT-image-2 as “state-of-the-art” and gives token-based image pricing categories, but the snippet does not expose full per-image costs [3]	Third-party sources claim Nano Banana/Nano Banana Pro can be materially cheaper per image, but exact figures vary across posts [5][14]	Likely Nano Banana, but confirm current API pricing
Ecosystem	GPT Image 2 fits OpenAI/ChatGPT workflows and API usage [1][3]	Nano Banana fits Gemini API, Google AI Studio, and Vertex-style workflows [2]	Depends on stack

Where GPT Image 2 seems better

• Use GPT Image 2 when the output must obey complicated instructions, object placement, scene logic, or precise layout constraints, because multiple comparisons describe it as stronger on spatial logic and multi-constraint prompts ^[10][14].

• Use GPT Image 2 for images containing readable text, signs, UI mockups, labels, packaging, diagrams, or posters, because comparison posts consistently identify text rendering as a major GPT Image 2 advantage ^[10][14].

• Use GPT Image 2 when you care most about benchmark rank, since third-party arena-style sources place it above Nano Banana 2 and report a large Elo lead ^[13].

Where Nano Banana seems better

• Use Nano Banana when you need explicit 4K output support through Google’s documented image-generation API, because Google’s docs list selectable output resolutions including 4K ^[2].

• Use Nano Banana when speed and cost matter more than maximum instruction fidelity, because third-party comparisons repeatedly position it as faster and more cost-efficient than GPT Image 2 ^[9][14].

• Use Nano Banana if your workflow already lives in Gemini, Google AI Studio, or Google’s developer tooling, because Google documents Nano Banana image generation directly in the Gemini API docs ^[2].

Evidence quality and caveats

• The strongest sources are the official OpenAI and Google docs for model availability, API support, pricing categories, aspect ratios, and resolutions ^[1][2][3].

• The weakest evidence is exact “winner” scoring from SEO-style comparison blogs, because many publish benchmark tables without transparent prompt sets, sample sizes, or reproducible methodology ^[10][13][14].

• Arena-style human-preference scores are useful for directional quality, but they can shift quickly as models update, prompts differ, and leaderboards separate text-to-image, editing, and multimodal tasks ^[8][11][13].

• Insufficient evidence is available from the search results to state a fully verified, reproducible benchmark suite covering all categories such as typography, photorealism, character consistency, editing, latency, cost, and safety under one methodology.

Practical recommendation

• Pick GPT Image 2 for: ad creatives with exact copy, infographics, product mockups, UI screenshots, diagrams, posters, multi-object layouts, and prompts where mistakes in text or relationships are unacceptable.

• Pick Nano Banana for: high-throughput generation, 4K-oriented workflows, quick visual ideation, Gemini-integrated apps, lower-cost production, and photorealistic or lighting-heavy images where exact text is less important.

• Best production strategy: route difficult text/layout/edit prompts to GPT Image 2, and route bulk, fast, high-resolution, or cost-sensitive prompts to Nano Banana.