Introduction

Hello, image tinkerers! This one is a Leak / Preview, not a launch. On Oct 28 (20:56 UTC), OpenAI's official openai-openapi repo gained a new markup field for the Image Edits endpoint. Its description says it "Supports GPT Image 2.5 and 2.6," and that's the first time OpenAI's own files have named GPT Image 2.6.

GPT Image is OpenAI's closed, API-only image model family. What you can run today is GPT Image 2.5 (gpt-image-2.5-sunburst and gpt-image-2.5-flare) in the OpenAI API and ChatGPT. GPT Image 2.6 has no model ID in the spec, no announcement, and no release date.

What the spec actually says

The new field sits on POST /images/edits, in both the file-upload form and the JSON form of the request:

  • What it is. markup is a transparent PNG laid over the first input image to guide the edit.
  • How to send it. The JSON form accepts a file ID, an HTTPS URL, or a base64 data URL.
  • Size rule. It must match that image's dimensions after orientation, and it must contain transparent pixels.
  • Model support. It "Supports GPT Image 2.5 and 2.6."
  • The catch. It "Cannot be combined with mask."

The model list in the same spec still stops at gpt-image-2.5-flare-2026-09-08, and the official Python SDK release that followed (v3.41.0, Oct 28) doesn't include markup yet. So treat both the field and the model as coming soon, not live.

Why markup is interesting

A mask tells the model where it may paint. A markup layer looks more like an art director's scribble on a print: arrows, circles, rough strokes or colour blocks on a transparent layer, showing what should change. If it ships as described, you could sketch a new window onto a building, circle a face to fix, or block in a colour for a jacket, then let the prompt explain the rest.

Here's a prompt you could pair with a markup layer once it's live:

Follow the red strokes on the overlay: turn the circled storefront into a glowing neon ramen shop at night, add the window where the rectangle is drawn, and keep the street, lighting direction and camera angle unchanged.

What else points to 2.6

  • Arena checkpoints. Community trackers tied three anonymous Arena image models (shooting-star-red-alpha, shooting-star-green-alpha and aurora-purple-alpha) to OpenAI around Oct 23–25. Nobody has confirmed that any of them is 2.6.
  • Early takes are mixed. Some testers call it a small bump over 2.5, and others hope it fixes 2.5's faint dot pattern and improves Chinese text.
  • Timeline so far. GPT Image 2 arrived in April 2026, the 2.5 snapshots are dated Sept 8, 2026, and gpt-image-1 was shut down on Oct 23, 2026.

Original Source

The leak was first flagged on X by Token Gremlin:

The primary artifact is OpenAI's own spec commit in the openai-openapi repo.

Conclusion

One line in a spec isn't a launch, but it's a real breadcrumb from OpenAI itself, and the markup overlay is the part to watch. Until 2.6 has a model ID, keep editing with GPT Image 2.5 and save a few transparent sketch layers for the day markup goes live. I'll be back the moment it ships!

—Aurelia ♡