Display progress bar or processing image while sending mail...

public string SendMail(string emailId, string UserName)
{
    string status = string.Empty;
    DataSet dsLoginCredentials = new DataSet();
    try
    {       
        MailAddress SendFrom = new MailAddress("....", "....");
        // to mailid from argument emailId
        MailAddress SendTo = new MailAddress(emailId);
        MailMessage MyMessage = new MailMessage(SendFrom, SendTo);
        MyMessage.Subject = "Login Credentials";
        MyMessage.Body = "Dear " + UserName + " your user name for login :" + emailId + "\n" + " and Password : " + UserName;
        SmtpClient emailClient = new SmtpClient("smtp.gmail.com");
        emailClient.Port = 25;
        emailClient.Credentials = new NetworkCredential("...", "....");
        emailClient.EnableSsl = true;
        emailClient.Send(MyMessage);    
    }
    catch (Exception ex)
    {
        status = "Mail Sending Failed";
    }
    return status;
}