CBR, ComicBook RAR Archive (.cbr)
The CBR eBook file format
CBR (Comic book archive or comic book reader file) files are utilized for the viewing and storage of comic book pages. Those images can be placed in specific order to allow the reader to get through the story in the intended order (like page numbers). Formatting can also be altered to allow two images to be seen next to one another — resembling the double page spread capabilities of printed comic books. Other sequences of images can use this archiving method as well, but it was originally created, intended, and commonly used for the electronic presentation of comic books. CDisplay image viewer popularized this file archive.
Technical details of CBR files
The majority of images within the CBR archives consist of lossless PNG files or lossy JPEG files in an archive using the RAR method of archiving. GIF, BMP, and TIFF files can be likewise used but are not as popular. Despite using the RAR archiving and compression, CBR files can be viewed directly by comic book viewer applications, bypassing the standard decompression stage. All images need to be decompressed, but this are not done at the beginning — meaning the reader can begin reading without decompressing the entire archive. Using embedded XML files, additional information may be found in the CBR file, much like metadata or audio and video, but also including text layers for language translation of the text in the images.