I believe the timeframe is one month. When you upload a document image to a profile, you can uncheck the little box for Use a primary photo, but still leave it attached to the profile. It will remain in the right side of the profile though.
If you like, you can upload the digital images to a free space and link from there. You could maybe do a general page about a surname and link corresponding documents. Maybe a family you are researching emigrated to say Massachusetts, but then later generations migrated west. You could write a little interesting short history to be the purpose of the space page, then upload your documents.