Comic book archives
Comic book archives are compressed archives with sequential images in them. They archives are named
.cbX where the
X indicates which archive format is used to contain the images. Comic book archives can be compressed and viewed with any image viewer or opened in a document reader capable of handling comic book archives.
The File Format
Comic book archives are simply archives containing sequentially named images in a common image format. It is not a very strict or predictable format. PNG and JPEG are most commonly used to store images in comic book formats but there are many archives with TIFF, GIF and BMP files in them. The archive container used to store the images is also variable. Comic book archives will have one of these extensions which indicates what kind of archive the images are in:
Free software document readers like Okular (Linux/Windows/macOS) and Zathura (Linux only) can open comic book archives as-is. Most image viewers can not, they simply have no idea what to do with a .cbr or a .cbz file. However, they can open the images inside the archives just fine so you can simply unpack a comicbook.cbz file and open it with geeqie or gpicview or any other image viewer. Doing so is not ideal since image viewers consider single images as their own thing. Document viewers provide a better experience because they rightfully consider each image to be a page in a series of pages.
Okular is the best choice on GNU/Linux if you want a fully featured comic book reader (capable of opening all other documents as well). Zathura is the best choice if you want a light-weight keyboard-driven (no mouse toolbar or navigation) comic book reader.