Cornice is a cross-platform image viewer written in Python + wxPython + PIL. Detail and thumbnail view for images. Automatic recognition of images, with a variety of formats supported. Image preview. Bookmarks. Full-screen view. Zooming and rotation. Slideshow. Good keyboard navigation (still not perfect, but this is true for all the features). Image loading from zip archives. i18n support (with Italian and French translations available). EXIF data support.
It doesn't pretend to be complete, fast, or even useful, but I like it and it is the viewer I use on Windows. It has been inspired by the famous Windows-only ACDSee. Why did I write it? Well, because I like ACDSee, but it's not free.