I have tried many graphics on many different computers, with versions of LibO for the past couple years. When exporting to PDF or sending as PDF to e-mail the graphics become distorted (triple image overlapp sometimes) or blank (Missing entirely). I have to print to Cute PDF to resolve this, but doesn’t help users who want to Send via e-mail to eliminate the many extra steps.
The problem(s) should be reported to bug tracker, individually for each case, with original documents used for export attached. This could allow developers to see and fix such problems.