Update Image Caption

Update the caption of a specific image. Two mutually exclusive options:

1. Provide a new caption: Use the caption parameter (sets caption_source to "manual"). The caption must be a string containing a valid JSON structure.
2. Regenerate automatically: Set regenerate_caption to true (sets caption_source to "automatic").

Constraints:

• Cannot update captions in a completed dataset
• Cannot provide both caption and regenerate_caption