[artemisart]

Yes, the idea works and was explored with dreambooth/textual inversion for image diffusion models.

https://dreambooth.github.io/ https://textual-inversion.github.io/

[minimaxir]

Both of those are of course out of date and require significant training instead of just feeding it a single image.

InstantID (https://replicate.com/zsxkib/instant-id) fixes that issue.

[Auracle]

Dreambooth style training is in no way out of date.

If you just want a face, InstandID/Pulid work - but it’s not going to be very varied. Doing actual training means you can get any perspective, lighting, style, expression, etc - and have the whole body be accurate.