Input for generating new images by recontextualizing existing product images.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v25/services/asset_generation_service.proto)

| Fields ||
|---|---|
| ## `prompt` | `string` Optional. A freeform description of the assets to be generated. Maximum character limit is 1500. |
| ## `source_images[]` | `https://developers.google.com/google-ads/api/reference/rpc/v25/SourceImage` Required. Product images to use for generating new images. 1-3 images must be provided. |