Seems fast and will create thumbs without needing to import. It's also cross-platform compatible for Windows, Mac and also Linux. Does not handle external drives very well though.
http://www.xnview.com/en/xnviewmp/#features

Technical notes, and other ideas.
Seems fast and will create thumbs without needing to import. It's also cross-platform compatible for Windows, Mac and also Linux. Does not handle external drives very well though.
http://www.xnview.com/en/xnviewmp/#features