|Python Imaging Library Handbook|
(New in 1.1.5) PIL provides a stub driver for GRIB files.
The driver requires the file to start with a GRIB header. If you have files with embedded GRIB data, or files with multiple GRIB fields, your application has to seek to the header before passing the file handle to PIL.
To add read or write support to your application, use the register_handler function in the GribStubImagePlugin module.