File talk:Sinking torpedoes by moonlight in Charleston Harbor - Harper's Weekly, June 13, 1863.jpg

I took this photo from the online database "Harpweek" containing the content from Harpers Weekly during the civil war period. I know that Harpers Weekly itself is long past copyright, and if I went to the library myself and scanned a page it would be in the public domain. However there is a license agreement attached to use of the Harpweek database restricting use of content to "Fair use." My question is, can Harpweek restrict my use of a digital form of an image that is otherwise in the public domain? I think the answer is no, that copyright protects creative expression and simply scanning all the issues of Harpers and putting them online behind a subscription wall does not qualify as creative expression. However I am open to other points of view.