IrfanView - IrfanView ... one of the most popular viewers worldwide.
calibre - Ebook manager, viewer & converter
ImageGlass - You can use Image to view your digital images and photos of many different formats.
FBReader - FBReader is an e-book reader for various platforms. Features:
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
Google Play Books - Google Play Books lets you search, preview, and buy millions of books using Google Book Search.