I know how to extract video from a live photo. Explained here.
Use the PHAssetResourceManager to get the video file from the PHAssetResource. 
PHAssetResourceManager.defaultManager().writeDataForAssetResource(assetRes, 
    toFile: fileURL, options: nil, completionHandler: 
  {
     // Video file has been written to path specified via fileURL
  }
But how to extract image URL from PHLivePhoto. The motivation behind this is to get both video and image URL in order to upload it to the server.