Showkase makes extensive use of 'alt' attributes for images throughout a site.
(1) In a Site Header logo, an 'alt' attribute is used, populated by the web site title (from 'Site -> Site Settings').
(2) In a Library image inserted into a page via the editor, an 'alt' attribute is used, populated by the 'Alternative Text' input on the editor's Image pop-up window.
(3) In a ListViewer gallery, 'alt' attributes are used, populated by the image titles (on the 'Images' tab).
(4) In a Juicebox gallery, 'alt' attributes are used in the dynamically generated code (populated by the image titles) and in the SEO content code (populated by the image captions). If you want SEO content code to be included in your Juicebox gallery pages, be sure to select the 'Add SEO Content' checkbox in the 'Gallery Lite Options' section. This is selected by default.
(5) Images within a SimpleViewer gallery are displayed as part of a Flash presentation and are not displayed using HTML <img> tags. However, you can still display SEO content code for SimpleViewer gallery pages and 'alt' attributes are used in the <img> tags here, populated by the image captions (on the 'Images' tab).
If you find any instances where 'alt' attributes are not used in <img> tags in a Showkase site, please let me know.
Thank you.