hi Guys,
There was a problem with some old design models inside The CentOS Artwork Repository which prevented centos-art.sh script from rendering images at preparation process. The exact problem was given because of a wrong path inside those old design models, specifically when centos-art.sh script verified them.
This problem was fixed and you should be able to render images right away, after updating your working copy of The CentOS Artwork Repository. Other changes were also committed. The exact changes can be found at: https://projects.centos.org/trac/artwork/timeline
Best regards,