Winnow is a Google Chrome add-on that provides a simple UI for browsing and downloading content (as opposed to UI or ad) images on a page.
Winnow is designed for advanced web users who view lots of photos and allows you allows you to view the images in a standardized, attractive viewer, for any site.
While the learning curve for setting up custom sites is steep, there will soon be a recipes page that users can use to add functionality.
Winnow only allows you to create rules for websites with image content; these rules contain filters, driven by regular expressions and XPath, that know how to parse the page for images and metadata.
Winnow is cross-platform and it works on Mac OS X, Windows and Linux.