Jim,
Here is more info.
Just got the info from my Windows colleague. The pictures were inserted
using "Insert... Picture....From file..." command. Picture is a JPEG. It
should not be a problem then. He is using Office 2003.
He sent me the images; they are JPEG, but large (high rez, approx +1MB). I
can open them with Preview, but if try to insert them with PPT using the
same "Insert picture from file",... I still get a black square!
But that's not all... If I open the images with Graphic Converter and save
them in PNG, I can now insert them in PPT and all is fine (but if I save
them in JPEG format from GC, I still get the "square"... Something wrong
with my Powerpoint?
Denis