Which protocol is best for sending raw, high-resolution design files via email?

The best protocol for sending raw, high-resolution design files via email is FTP (File Transfer Protocol). FTP is specifically designed for transferring large files across a network, making it well-suited for handling high-resolution design files that often exceed the size limitations of standard email attachments.

In contrast, SMTP (Simple Mail Transfer Protocol) is primarily used for sending emails and is subject to size restrictions dictated by the email server's configuration. This can make it impractical for very large files. HTTP (Hypertext Transfer Protocol) is typically used for transferring web pages and web content, rather than for direct file transfer between users. Finally, POP3 (Post Office Protocol 3) is designed for retrieving emails from a mail server and does not facilitate sending files at all. Therefore, FTP stands out as the optimal choice for the specific task of transmitting large design files.