ByteDance has been working on autoregressive image generation for a while (see VAR, NeurIPS 2024 best paper). Traditionally they weren't in the open-source gang though.
The VAR paper is very impressive. I wonder if OpenAI did something similar. But the main contribution in the new GPT-4o feature doesn't seem to be just image quality (which VAR seems to focus on), but also massively enhanced prompt understanding.
