There is an increasing trend on the part of museums to open their archives of public domain images and offer these images free for academic publications, provided they fit certain criteria such as a limited print run.
Free Images for Academic/Scholarly Use
Many institutions discount fees for academic publications, and fee-based image banks frequently have similar policies. Many image banks have reciprocal arrangements with non-US collections.
Fee-Based Image Banks
Some of the organizations listed below offer discounts for bulk orders and scholarly publications.
Images cannot be used, without permission from the vendor, for:
All commercially produced maps are covered by the copyright law. The name of the copyright holder and the word "copyright" or symbol "©" will usually be printed or displayed somewhere on the map. However, even if unauthorized copies without copyright identification are subsequently reproduced, copyright laws and penalties still apply.
The University of Texas' Perry-Castañeda Library Map Collection - one of the largest collections of government and public domain digitized maps.