My Omeka site features an image archive of mostly artwork. I’m checking with librarians at my university, but I think it would help my fair use claim and relations with artists who have provided images if I could block image downloads in Omeka. Is this possible?
Could you clarify the fair use concerns at work here?
Anything that appears in the browser can be downloaded (indeed, it already has been). Omeka creates derivative images for display from whatever is uploaded, but does store the original file that was uploaded. There are ways to conceal access to the original file uploaded, and more complicated things can block access.
Depending on the fair use considerations, it might be much easier to do some work on the images before they are uploaded to Omeka. For example, if the major fair use consideration is market impact, then you could only upload files that are of low enough quality to not affect impact and income for the artists, but still good enough for the web.
The plugin Archive Repertory contains an anti-download feature (with modification of the file .htaccess). Perhaps it may be enough in your case.