OpenAI fixes image encoding bug affecting GPT-6 Sol and Luna
OpenAI says a bug in image encoding degraded image understanding in GPT-6 Sol and GPT-6 Luna. The fix improves visual-task results in the API and Codex, including computer use; OpenAI recommends rerunning evaluations and retrying affected image-input workflows.
SessionWatcher editorial · Published · Updated · Source announcement: 2026-09-25
Image understanding fix
OpenAI's September 25 changelog says it fixed an image-encoding bug that degraded image understanding in GPT-6 Sol and GPT-6 Luna. The update improves results on visual tasks in the API and Codex, including computer use.
Sources: Openai release notes: 2026-09-25
What to do if you use image inputs
If your workflows use image inputs, OpenAI recommends rerunning evaluations and retrying workflows affected by the issue. The note does not specify how to identify every affected workflow or quantify the improvement, so retest your own image tasks rather than assuming results will change by a particular amount.
Sources: Openai release notes: 2026-09-25
AI assisted reporting, checked against the linked official sources. Source pages checked 2026-09-30. Editorial process and corrections.