[twg-tds] Question: how to include an image file in a document class?

[Karl Berry]

    I read somewhere someone says all image files like .png should go to
    /doc folders as required by TDS

Not *all*.  

Most image files are part of the documentation, therefore would go in
the doc tree.  If an image file is needed at runtime, it clearly has to
go in the tex tree.  The placement of any given file depends on how the
file is used.  There are no absolute rules based simply on file
extension; such inflexibility would not be useful.  -k