GitHub lets you download the whole repository as a Zip file, instead of having to clone. On the top-right of the page, the option should be there.
The easiest way you'd do it is to put the GIFs in the same directory as the script, and change the working directory with the cd command to the directory. Run the command like so, but prefixed with Python, as you may be missing the executable bits or running Windows:
'USAGE: hgrdither.py [outputfilename] [inputgif] [brightness (float of order 1.0)] [videosize (normal,small,tiny)]'
I'd imagine it'd look something like "python hgranimate.py whatever whatever.gif 0.5 normal" - adjust as needed?
Edited by IPalindromeI, 07 January 2017 - 08:25 PM.