• Autoregressive model
• Multimodal with the LLM
• Can keep consistency between images
• Much better at text rendering
• Can combine images, like you have one image and you upload a picture of a jacket and say "put this on him" and it does it
• Can upload a picture of yourself and say "put me on the beach", and then for example if you don't like it you can tell it to do a different type of beach, and then say "and put me on a white horse and give me some nice beach wear" for example.

It understands what you're telling it, and can generate images from vague descriptions, combine things from different images just by telling it, modify it and understand the context - like knowing that "me" is the person in the image, for example.

Edit: From OpenAI - "4o image generation is an autoregressive model natively embedded within ChatGPT"