AsyncImageTask

{
    "id": "task_img_abc123",
    "task_id": "task_img_abc123",
    "taskId": "task_img_abc123",
    "object": "image_generation.task",
    "model": "gpt-image-2-pro",
    "status": "queued",
    "progress": 42,
    "created_at": 1735689600,
    "completed_at": 1735689720,
    "expires_at": 1735776000,
    "size": "1536x1024",
    "data": [
        {
            "url": "https://example.com/images/img-abc123.png",
            "b64_json": "iVBORw0KGgoAAAANSUhEUgAA...",
            "revised_prompt": "一张现代 API 平台首页插图，白底，青蓝色块，干净留白"
        }
    ],
    "error": {
        "message": "prompt is required",
        "type": "invalid_request_error",
        "param": "prompt",
        "code": "invalid_request"
    }
}