imagePickerControllerImplementation.swift

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        picker.dismiss(animated: true, completion: nil)

        // 1. Get image data from selected image
        guard let image = info[UIImagePickerControllerOriginalImage] as? UIImage,
            let imageData = UIImageJPEGRepresentation(image, 0.5) else {
                print("Could not get Image JPEG Representation")
                return
        }

        // 2. Create a unique image path for image. In the case I am using the googleAppId of my account appended to the interval between 00:00:00 UTC on 1 January 2001 and the current date and time as an Integer and then I append .jpg. You can use whatever you prefer as long as it ends up unique.
        let imagePath = Auth.auth().app!.options.googleAppID + "/\(Int(Date.timeIntervalSinceReferenceDate * 1000)).jpg"

        // 3. Set up metadata with appropriate content type
        let metadata = StorageMetadata()
        metadata.contentType = "image/jpeg"

        // 4. Show activity indicator
        showNetworkActivityIndicator = true

        // 5. Start upload task
        storageUploadTask = storageRef.child(imagePath).putData(imageData, metadata: metadata) { (_, error) in
            // 6. Hide activity indicator because uploading is done with or without an error
            self.showNetworkActivityIndicator = false

            guard error == nil else {
                print("Error uploading: \(error!)")
                return
            }
            self.uploadSuccess(imagePath, image)
        }
    }