Image cropping in the Agent API - stitch setting doesn't work

While setting up an agent, I tried doing

"presenter": {
        "type": "talk",
        "voice": {
            "type": "elevenlabs",
            "voice_id": "21m00Tcm4TlvDq8ikWAM"
        },
        "source_url": "https://test.com/image.jpg",
        "thumbnail": "https://test.com/image.jpg",
        "config": {
            "stitch": True
        }
    }

However it is still cropping around the face. How to fix it for Agents?