Desmith

I have downloaded the latest version of the software and it appears my issues have been resolved

I'm having a similar issue.  Put together a 15 minute slide show with music.  It looks great it full screen preview, exactly what I wanted.  When I export, with Letterbox, the majority of the landscape photos and the initial title screen and ending credit screens are center and much smaller.  The portrait photos fill the screen nicely.  I've tried multiple settings on the export and can't find any that produce the same version as seen in the preview screen.