If you already have the reference face (like the user profile picture), extract the descriptor of both the selfie and the reference image, and compare them.

```javascript

async function compareFaces(image1, image2) {
    const detections1 = await detectFace(image1);
    const detections2 = await detectFace(image2);
    
    if (!detections1 || !detections2) {
        return false;  // No face detected
    }

    const distance = faceapi.euclideanDistance(
        detections1.descriptor, detections2.descriptor
    );

    const MATCH_THRESHOLD = 0.6;  // Set an appropriate threshold
    return distance < MATCH_THRESHOLD;  // If distance is below the threshold, the faces match
}

```