I have heard that metadata can leak original IP when uploading files to a server using Tor. Is this correct? How can I upload and download safely small files to and from a server? Files are smaller than 1 mb.

I have heard that metadata can leak original IP when uploading files to a server using Tor. Is this correct? How can I upload and download safely small files to and from a server? Files are smaller than 1 mb.
Embedded metadata can leak many kinds of identifying information, but it's unlikely to leak the "original IP".
Tails ships the MAT, by the way.