Picture generated by Mycelium Entropy is built from fragments according to
layout.c. See comments in
jpeg.c about fragment types. Fragments are generated by
tools/gen.py and written into
jpeg-data* files, which are then linked into the firmware image.
Results can be tested without an Entropy device. In the
tools sub-directory, run
make check to build the
check.c, from auto-generated
jpeg-data* files and other sources. Then run the
check executable (a
--help argument shows usage notes).
There is currently no tool to help customise the output picture.