seems when adding treenodes "runtime" the images are not rendered. I modified your FeaturesDemo Project, AdvTreeView.pas not loading the treeitems in the oncreate-event of the form but by clicking a button and the images are not visible. I'm working with Intraweb 15.1.0.
I have not been able to reproduce this in the FeaturesDemo.
You can email sample project as attachment to mailto:firstname.lastname@example.org
Sample sent by mail.