Metadata: Add a flag that Controlnet was used on sample images when it was

Hi! Love the site and upload models on occasion. I've had a couple reviews negatively comment that the samples on a model are better than what can actually be generated. Further that they're not reproducible.

I often use controlnet to generate images that I use for samples, and in most cases that makes them hard if not impossible to replicate for the end user. Unless I'm missing something or have a bad setting, it doesn't seem like there is a flag or note if Controlnet has been used to assist in generating an image. I'd love to either see that full metadata added to images (at least sample images) so that users can understand why an image is not turning out the same way even though they copied the prompt/seed/models/etc.

Thanks for considering!