CBZ
Also known as: .cbz file, comic book ZIP, comic book archive
CBZ is a comic-book file format that is simply a ZIP archive of image files — one image per page — renamed with a .cbz extension. Comic readers open it, sort the pages by filename, and display them in order.
- A ZIP archive of page images, renamed .cbz
- Pages display in filename order
- Open ZIP-based alternative to RAR-based CBR
How CBZ works
A .cbz file is a plain ZIP archive. Inside are the page images (usually JPEG or PNG) named in reading order, plus an optional metadata file. Rename a .cbz to .zip and any unzip tool will open it; comic apps just read it directly.
Because it is a container of images, the file size is the sum of its pages. A long, high-resolution color comic can run to tens or hundreds of megabytes, while a short black-and-white issue is much smaller.
CBZ vs CBR and other comic formats
CBZ uses ZIP compression and CBR uses RAR; the only real difference is the archive format wrapped around the images. CBZ is generally preferred because ZIP is an open, universally supported format, whereas RAR is proprietary.
To save space, you can re-compress the page images or convert a comic to PDF or EPUB. The pages themselves — not the archive wrapper — drive the size.