Among the features it provides are: full screen, preview, thumbnail view with details, and loads of image effects (sepia, blur, and the like). It’s definitely sufficient for any of your image viewing needs and it’s quick to make simple image touches without having to launch Gimp. (although, at least in my computer, Gimp launches much quicker than Photoshop)
For my photo album / image library needs though, I still prefer Google Picasa.
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