calibre - Ebook manager, viewer & converter
Manganelo - Manganelo is an online application for manga lovers that offers millions of Manga to read and share.
NeeView - Display two images simultaneously
CDisplay Ex - CDisplay Ex is the most used comic book reader.
FBReader - FBReader is an e-book reader for various platforms. Features:
HoneyView - HoneyView is a fast image viewer that supports archived image file for comics/manga/photos.