Switch -MS[list] - specify file types to store
Specify file types, which will be stored without compression. When used properly, it helps to increase archiving speed without noticeable loss in the compression ratio.
Optional <list> parameter defines the list of file extensions separated by semicolons. For example, -msrar;zip;jpg will force WinRAR to store without compression all RAR and ZIP archives and JPG images. It is also allowed to specify wildcard file masks in the list, so -ms*.rar;*.zip;*.jpg will work too.
If <list> is not specified, -ms switch will use the default set of extensions, which includes the following file types:
7z, ace, arj, bz2, cab, gz, jpeg, jpg, lha, lzh, mp3, rar, taz, tgz, z, zip