Google Picasa on Windows comes coupled with an awesome image-viewer.
Of course, in order to use the photo viewer you do need to have Picasa 3.0 beta installed.
What is Picasa Photo Viewer?
From the Google Photo Blog: -
We designed Photo Viewer to be a better, faster image viewer. A quick double-click on any photo will give you a beautiful full-screen view (with Picasa edits applied) and puts a select few options at your fingertips: you can quickly rotate an image, star it, upload it to your Picasa Web Albums drop box, or play a slideshow with other photos from the same folder.
What else can it do? Tap the scroll wheel on your mouse to discover how nice it is to have a fast, smooth zoom at hand when reviewing your photos, or try the ‘More Options’ button to bounce an image to your printer, blog, or favorite photo editor.
Install Google Picasa Photo Viewer
Download the .deb @ http://www.caiacoa.de/Transfer/PicasaPhotoViewer-1.0.3.deb
Now you can open a photo with the viewer by right-clicking and then open with > custom command > PicasaPhotoViewer
Set As Default
To set it as the default image viewer right click an image > properties > open with > PicasaPhotoViewer.