The image/document space of your Mailpro account is a public space used to link/embed the images/documents you send with your Mailpro campaigns and messages. You should not store there any confidential or sensitive files.
In other words, if you put a file on Mailpro’s server by uploading it to the image/document space of your Mailpro account, it’s because you want people to download it or have access to it through the email messages you send. Also you have to be aware that the file can be downloaded by anyone who knows the image/document link.
If the file is confidential or sensitive, then you need a Backoffice with user/password and not a public link shared on Internet. Never link these files from URLs available on the Internet, because they can be indexed by WebCrawlers and be publicly available online.