You are right, I previously declared the artwork directory to the giant "EXTRAs" archive only so the local directory was ignored, however as solution I have choosen to copy the few artwork files in mame source distribution to the main directory where all the complete artwork set lives. In this way a single artwork path does the job once for all.
It could also be not a bad idea to include this default artwork set also in the main EXTRAs distribution as zipped archive naming it as "default.zip" for example so a single distribution include everything is needed.

After the correction above the result is perfect, many thanks for pointing me in the right direction!

Chess 2001 with all pieces at their place

Last edited by MacBox360; 11/05/19 07:20 PM.