Please note:
There have been previous threads discussing the
DPI settings & scaling of images when generating PDF format documents. (The defaults are for 72dpi “screen resolution”, not “print resolution” at 300-2400dpi.)
Also Note:
One of the strong contributors to the above discussions was @PLegoux
Patrice is a leading contributor in the Gramps subgroup on the Geneanet forum, where discussions are in French and illustrations use that localized GUI.