[GrantS]

OpenAI announced and released CLIP on GitHub on January 5, 2021: https://github.com/openai/CLIP

You need CLIP to have CLIP guided diffusion. So the current situation seems to trace back to OpenAI and the MIT-licensed code they released the day DALL-E was announced. I would love to be corrected if I've misunderstood the situation.

[naillo]

You're totally right, OpenAI released CLIP in january. But I mean CLIP isn't an image generator, it's just a classifer. If we restrict the question to actual text to image generators (ignoring deep dream or some of the 'kinda cool but far from the coherency of post-2021 generators') then clip guided diffusion is kinda the first.