A CBR file is a Comic Book Archive file. It's essentially a renamed RAR archive containing a series of image files, typically in JPEG, PNG, or GIF format, representing the pages of a comic book. The images are sequentially numbered to allow comic book reader software to display them in the correct order. CBR files are a popular way to distribute and read digital comics, as they offer a convenient way to package and view an entire comic book in a single file. The format is widely supported by various comic book reader applications across different platforms. The RAR compression allows for a smaller file size compared to simply storing the images individually, making it easier to share and download comics. While the extension is '.cbr', the underlying structure is based on the standard RAR archive format, so standard RAR archive tools can sometimes be used to extract the images, although dedicated comic book readers provide a more user-friendly reading experience.