h5ai is awesome. The interface is fine. The problems I had were that the process of generating thumbnails is pretty opaque. It appears to start generating them when a directory is first visited through a browser, via a background task. However, it seemed like maybe the process stopped if you closed the page before it finished. So it became sort of this dance where I'd leave the browser open and monitor Top to see when the process finished. But even then sometimes it would freeze and thumbnails and previews would never load. Also it doesn't appear to do on-demand loading, so if you have a ton of photos in one directory it takes forever to load. The single and multi download features are perfect though.