You can send and receive messages up to 10 megabytes (MB) in size, including attachments. Incoming messages over 10 MB will be returned to the sender without being delivered to you.
With Gmail, you can send and receive messages up to 10 megabytes (MB) in size. However, the precise amount allowable will depend on the attachment.
When you add an attachment, the size of a file may increase because transport encodings are automatically added. (Transport encodings are the information that allows your message to be safely sent and read.)
This means that in some cases, attachments that are 6 to 10MB in size may push the total message size above 10MB. When this happens, Gmail displays a warning that your message exceeds the 10MB limit.
大約是10MB吧
GMAIL我有在用,2GB的空間的確不錯用,我都是拿來用作寄件備份,寄出的信都會多一份密件副本到GMAIL,這樣有時就能把寄件備分清一下,公司的MAIL只有50MB

,但是有時會發生被退信的情況,不穩定這應該是使用免費資源的最大代價吧!