This Mac app was originally created by Diiva Associates. The software is included in Internet & Network Tools.
From the developer:
Diiva is a newsreader for images that lets you browse through the encoded pictures in newsgroups more easily than any other program. It's able to automatically categorize images, display image previews, and manage your archive of downloaded pictures.
You may want to check out more software for Mac, such as Wii Video 9, SlashDock or Universal RSS Reader, which might be related to Diiva X.