MFMailComposeViewController taking ages to send email

I'm building an app in which I need to attach and send multiple photos in an email. To accomplish this I save the photos to disk in the camera VC and access them in the viewDidLoad() of the email VC. I store them as .pngData() in a array and attach them in the MFMailComposeViewController using this code:

func configuredMailComposeViewController() -> MFMailComposeViewController {

    let mailComposerVC = MFMailComposeViewController()
    mailComposerVC.mailComposeDelegate = self

    mailComposerVC.setToRecipients([UserDefaults.standard.string(forKey: "Email")!])
    mailComposerVC.setSubject("Заявление")
    mailComposerVC.setMessageBody("\(ProtocolText.text!)", isHTML: false)

    // unpacking images from array and attaching them to Email

    var dataName = 0
    for data in imageData {
        dataName += 1
        mailComposerVC.addAttachmentData(data, mimeType: "image/png", fileName: "\(dataName).png")
    }

    return mailComposerVC

}

These are my "save" and "get" methods:

func loadImage(fileName: String) -> UIImage? {

    let documentDirectory = FileManager.SearchPathDirectory.documentDirectory

    let userDomainMask = FileManager.SearchPathDomainMask.userDomainMask
    let paths = NSSearchPathForDirectoriesInDomains(documentDirectory, userDomainMask, true)

    if let dirPath = paths.first {
        let imageUrl = URL(fileURLWithPath: dirPath).appendingPathComponent(fileName)
        let image = UIImage(contentsOfFile: imageUrl.path)
        return image

    }

    return nil
}

    // Used in CameraViewController
func saveImage(imageName: String, image: UIImage) {


    guard let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else { return }

    let fileName = imageName
    let fileURL = documentsDirectory.appendingPathComponent(fileName)
    guard let data = image.jpegData(compressionQuality: 1) else { return }

    //Checks if file exists, removes it if so.
    if FileManager.default.fileExists(atPath: fileURL.path) {
        do {
            try FileManager.default.removeItem(atPath: fileURL.path)
            print("Removed old image")
        } catch let removeError {
            print("couldn't remove file at path", removeError)
        }

    }

    do {
        try data.write(to: fileURL)
    } catch let error {
        print("error saving file with error", error)
    }

}

For some reason the images attach but the email takes at least 15 seconds to send. The "send" button just gets stuck. I don't know why. Please help.

It was a problem with the weight of the image. One image used to weigh 6848.7939453125 KB. Since I had multiple images it took a lot of time to process them. Compressing them using the image.jpegData(compressionQuality: CGFloat)!) method solved all problems. Thank you Mark Thormann for suggesting the fix!