TOAST.net's mail systems can send and receive messages up to 25 megabytes (MB) in size. This means you will be able to send and receive messages up to 25 megabytes (MB) in size (depending on your email account type). Do keep in mind that the precise allowable size will depend on the attachment.
When an attachment is added to an email, the file size may increase due to "transport encodings" that are automatically added. (Transport encodings are additional pieces of information added to the attachment so it can be safely delivered and read.) With this additional encoding, it is possible that an attachment under the limit may not be able to be sent. It is not recommended sending an attachment over 18MB.
Also note that attachment limits vary on other email services, so an email sent with a large attachment may be returned if it exceeds the contacts's attachment size rules. Suggest the contact switch to TOAST.net if your message bounces.