The technology behind GPT Image 1.5
How the model works, based on public documentation and sourced evidence.
GPT Image 1.5 is OpenAI's natively multimodal image model: one system reads your text and reference images and generates the picture directly, instead of passing a prompt to a separate image engine. The GPT Image family grew out of the image generation OpenAI built into GPT-4o, which works autoregressively, building the image piece by piece the way a language model predicts the next word. That design is why the line is known for following instructions closely and rendering readable text.
OpenAI announced GPT Image 1.5 on December 16, 2025 as the model behind the new ChatGPT Images. The headline improvements over GPT Image 1 are stronger instruction following, precise edits that change only what you ask for while keeping lighting, composition, and a person's likeness intact, and generation up to 4x faster. OpenAI also says it handles denser and smaller text than before, which matters for posters, packaging, and UI mockups.
In the API the model is called gpt-image-1.5 and prices per image range from about $0.009 for a low quality 1024x1024 image to $0.20 for a high quality 1536 resolution image, with image tokens about 20% cheaper than GPT Image 1. It accepts text and image inputs only, and does not support fine-tuning or streaming.
OpenAI's own documentation is upfront about limits: complex prompts can still be slow, very dense or tiny text can degrade, recurring characters are hard to keep consistent, and precise composition control remains difficult. On provenance, images made with ChatGPT and the OpenAI API carry C2PA metadata, and as of May 2026 OpenAI also embeds Google's SynthID watermark, with a verification tool that checks whether an image came from OpenAI's models.