ChatGPT Images 2.5 vs Nano Banana 2: Which One is Better?

In brief

• ChatGPT Images 2.5 launched September 8 with sharper detail, more precise editing, and up to 50% lower latency than its predecessor
• Across six fresh test categories, Nano Banana 2 won three, with ChatGPT Images 2.5 taking the other ones
• The swing came down to a few checkable mistakes instead of very noticeable issues.

OpenAI shipped ChatGPT Images 2.5 on September 8, and the pitch was specific: sharper details, richer textures, more natural lighting, and editing that actually respects what you didn't ask it to change.

The company says image-generation latency dropped by as much as 50% compared with Images 2.0, and two new models—GPT-Image-2.5 Flare and GPT-Image-2.5 Sunburst—now sit in the API, with Flare as the fast default and Sunburst built for premium editing precision.

It's the direct sequel to a comparison we ran back in May, when GPT Image 2 and Nano Banana 2 traded wins across eight categories. GPT Image 2 took more of them but suffered from a distinctive oversharpening artifact whenever a prompt piled on too many constraints. That review closed with a specific question hanging over it: would OpenAI's next model fix that problem?

So we ran it back.

Same evaluator's eye, six categories carried over or adapted from earlier rounds, same prompts fed to both models. Google's side of the test uses Nano Banana 2—Google's name for Gemini 3.1 Flash Image—not the slower, more deliberate Nano Banana Pro.