How to send Email with more than 25 MB attachment

well, the capacity is not limited by C# but by the Email Service Providers. For Gmail, 25MB is the max. In case if you're trying to send email attachment bigger than the limit, your email will be bounced back by the email service provider be it Hotmail, Yahoo, Gmail etc. So, the solution is you can look for any provides a bigger attachment size, though AFAIK there's none. Hope it helps!