Base::base64 PHP Method

    function base64($data, $mime)
    {
        return 'data:' . $mime . ';base64,' . base64_encode($data);
    }

 /**
  * get captcha image and store key to session
  * @param \Base $f3
  */
 public function getCaptcha(\Base $f3)
 {
     $data = $f3->get('POST');
     $return = (object) [];
     $return->error = [];
     // check if reason for captcha generation is valid
     if (isset($data['reason']) && in_array($data['reason'], self::$captchaReason)) {
         $reason = $data['reason'];
         $im = imagecreatetruecolor(1, 1);
         $colorText = imagecolorallocate($im, 102, 200, 79);
         $colorBG = imagecolorallocate($im, 49, 51, 53);
         $img = new \Image();
         $imgDump = $img->captcha('fonts/oxygen-bold-webfont.ttf', 14, 6, $reason, '', $colorText, $colorBG)->dump();
         $return->img = $f3->base64($imgDump, 'image/png');
     } else {
         $captchaError = (object) [];
         $captchaError->type = 'error';
         $captchaError->message = 'Could not create captcha image';
         $return->error[] = $captchaError;
     }
     echo json_encode($return);
 }