The module jpeg provides access to the jpeg compressor and
decompressor written by the Independent JPEG Group
(IJG). JPEG is a standard for
compressing pictures; it is defined in ISO 10918. For details on JPEG
or the Independent JPEG Group software refer to the JPEG standard or
the documentation provided with the software.
Treat data as a pixmap of width w and height h, with
b bytes per pixel. The data is in SGI GL order, so the first
pixel is in the lower-left corner. This means that gl.lrectread()
return data can immediately be passed to compress().
Currently only 1 byte and 4 byte pixels are allowed, the former being
treated as greyscale and the latter as RGB color.
compress() returns a string that contains the compressed
picture, in JFIFformat.