建议支持base64， 参考response_format参数

[codingdimon]

https://platform.openai.com/docs/guides/images/usage?context=node&lang=curl

Each image can be returned as either a URL or Base64 data, using the response_format parameter. URLs will expire after an hour.

[Feiyuyu0503]

openai的dall-e-3是1小时，coze的图是一年之后过期吧。之后考虑支持base64。