How to obtain a talking_photo_id for a newly uploaded image?

I would like to generate a video using the talking_photo_id in the Create a Video API.
However, the documentation states that available talking_photo_ids should be retrieved from the following API:

POST: https://api.heygen.com/v2/avatars

When I actually retrieve them, it appears that talking_photo_ids are only assigned to images that have already been used to generate videos. With this behavior, it seems there is no way to obtain a talking_photo_id for a newly uploaded image.

Previously, with
POST: https://api.heygen.com/v2/video/av4/generate,
it was possible to upload an arbitrary image to

POST: https://upload.heygen.com/v1/asset,

and then generate a video using the returned ID. However, the ID obtained in that flow is not a talking_photo_id. As a result, with the current API
POST: https://api.heygen.com/v2/video/generate,
it seems that video generation cannot be initiated immediately after uploading an arbitrary image.

Is there a way to upload an image and then obtain its corresponding talking_photo_id?

Thank you for your assistance, and I appreciate your confirmation on this matter.