preview panel goes blank.

Hi folks,
After a serious session of downloading, something has gone amiss w/ the preview pane (when you choose an aircraft & it's picture is shown before you take it out for a fly. The one you can spin around w/ the mouse). When I choose a plane it's image comes up for a second & then it goes white. it doesn't happen to every plane. usually the ones without thumbnails. I re-installed FSX to no avail.
Any thoughts?
😳 Dexptchang