Steps to reproduce:
1. Add a RadPanorama to a form
2. Set the PanelImage to (none)
3. Run the project and you will see that the default image will be applied.
At this time it seems that there is no way to prevent the default image from being applied. Until a decent solution is found (if any), this property is removed from the designer.
COMMENT: This property should not be supported in design-time, because it is modified by each theme