Attachments up to 10 MB are allowed for messages sent from Seller Central for specific contact reasons. If you use your own email service (for example, Outlook), the 10 MB limit is for email text and any attachments combined.
You can send one or more attachments (up to 10 MB) in your replies to a buyer's message. Buyers can send one or more attachments (up to 10 MB).
The following formats are supported: