NeeView - Display two images simultaneously
calibre - Ebook manager, viewer & converter
ComicFlow - ComicFlow is an iOS app that allows you to read comics by opening .cbr or .
Sumatra PDF - Sumatra PDF is a slim PDF/DjVu/EPUB/XPS/CHM/CBR/CBZ/MOBI viewer for Windows.
ComiXed - ComiXed seeks to be the ultimate digital comic book management system.
Adobe Digital Editions - ebook reader software