July 22, 2011, 04:01:26 pm
To state clear, import Speedtree File in Lumion Tree\Plants\Custom\ etc.
Load a neutral environment, place the tree. Use select button, click the small Tree icon by holding ctrl. and then on the Tree-Symbol (your wrong thumbnail) by holding ctrl too, in the bar.
On Windows Vista and up, you have to be in admin mode during starting lumion, otherwise the thumbnail could not be saved in lumion dir.