For Digital Commonwealth (https://digitalcommonwealth.org/), we just use 
the title as the alt tag on both the search results and item detail page.

Search results: 
https://www.digitalcommonwealth.org/search?f[collection_name_ssim][]=Boston+Brewery+Posters&f[institution_name_ssim][]=Boston+Public+Library

Item detail: 
https://www.digitalcommonwealth.org/search/commonwealth:t435gm075

I'm curious to hear whether others feel like redundancy of title or 
description metadata in image alt tags is a problem. What other 
information are people including in the alt tag?

Thanks,
Eben

Eben English | Boston Public Library
Web Services Developer
617-859-2238 | [log in to unmask]