Rated 5 out of 5 stars

New comment to version 0.19.7:
It is now one of the best Firefox-add-ons, working very good!!! It is my standard for saving web-sites! Thank you!

This review is for a previous version of the add-on (0.9.1). 

By default, Mozilla Archive Format will archive exactly what the browser would save when you select the "Web Page, complete" option in the "Save As" dialog box.

However, if you enable the integrated Save Complete extension from the preferences, usually all the images will be saved.