Max. backup file size to upload to Dropbox?

Hi there!
I got Snapshot working for all the sites in my multisite install. Nice!
All of them upload nicely to Dropbox, except 1: the site with a backup zip of > 1GB.

There are some MP3's but most are images I guess of the 800+ blogposts I wrote.

What can I do to manage this problem?

Thanks for helping and thinking with me!