You can upload files to 3 places:
When you upload files to a task then you'll see preview images when available and supported. This mainly works with images and videos.
You can upload files from your computer directly to Breeze or link them from one of the cloud service providers. The main and important difference is that when you use the cloud service providers then the files are not uploaded to Breeze. Only the link to the file is saved in Breeze. This gives you more control over the permissions and access.
You can upload files from Google Drive, Dropbox, Box, OneDrive, and Evernote.