Hi, Jim,
We have a known issue with regards to updating images and saving in QuarkXPress 7.2. This issue has been resolved and will be in our next maintenance release which will be available for free in the next couple of weeks.
In the meanwhile, and for projects previously saved with the "file bloat," appending a layout into a new project will reduce the size. Create a new project, then go to File > Append... select the original project and choose to append Layouts.
Regards,
Thomas Allen
Product Manager, QuarkXPress
Quark, Inc.