A .cbr file is a compressed file that allows a set of comic book images to be stored. These images can be ordered and the format in which they are displayed can be altered to allow two images to be viewed side by side, in the same way as a double page spread would occur.
A .cbz file is actually just a .zip file with an amended file extension. What makes a .cbz file different is that it can be opened directly by comic book viewer applications without a requirement to decompress it first. The user can also associate the file extension with a comic book viewer application. Typical image formats are allowed for a .cbr file such as JPEG, GIFF, TIFF and PNG.
The file type .mobi is an eBook format created by a French eBook company called Mobipocket which created a free software application for multiple devices including PDAs, smartphones and tablet devices. The company was bought by Amazon in 2005 and the support of the .mobi file extension was officially discontinued in 2011 with the AZW format superseding it.
Amazon Kindle Apple iBooks Mobipocket Reader Desktop