I would guess that your PDF utility may be rendering any graphics in the PDF at a lower resolution.
For the "slight" size change issue, check acrobat's printing options and make a different selection before printing. You may find you have an option such as "shrink to printable area" enabled. (Wording and location of this option varies with the version of acrobat and whether you're using Mac or Windows.)
thank you for advice. I have checked size of jpeg. picture on the report, made them much smaller and the main issue is solved. Still did not find how to set up acrobat reader to adjust printing but it is not that crucial.
It's critical if you ever PDF a page of labels.
It's an option that should appear in your print dialog when you choose to print the PDF.
On Windows, Acrobat Reader 9, it shows in the Scaling drop down under page handling.