What is a CBR or CBZ file?

Definition

A CBR or CBZ file, also known as Comic Book Archive or Comic Book Reader file, is an archive file for the purpose of sequential viewing of images, generally comic books.

A renamed RAR or ZIP file

As the first two letters imply, CBR or CBZ files are normally used to pack comic books. The third letter identifies the archive format, the most widely used formats being:

• CBR: RAR
• CBZ: ZIP

Comic Book Archive files are, in fact, RAR or ZIP files with their extension renamed. CBR files are the most common, which is the reason these are also called Comic Book Reader files.

Other archive formats

The following extensions are rarely used, but are supported by most comic book viewers:

• CB7: 7-zip
• CBT: TAR
  
• CBA: ACE

Inside the archive

Comic Book Archive files are composed by a series of images, tipically JPEG or PNG files. GIF, TIFF and BMP are also supported by most comic book viewers.

Comic Book Archive files can also contain text files that some comic book viewers display when opening the file.

Adoption

The Comic Book Archive format was made popular by the CDisplay image viewer, which has now been discontinued by its original author. There are now many comic book viewers that support this format.

The most common use of Comic Book Archive files is the illegal distribution of scanned comics over P2P networks. The format has been so widely accepted that in the last years various publishers and creators have started to offer their comics in this format.