If you're optimizing it for download I'd say its arguably more important to avoid raster maps in favour of vector ones - resizing the cross hatching of a raster map can make it look horrible.
Secondly when your limited on colour palette and resolution doing a hierarchy of maps is better than fitting everything onto one image, say an overview of europe without any of the detail internal to the HRE and then an inset of the German states.
Secondly when your limited on colour palette and resolution doing a hierarchy of maps is better than fitting everything onto one image, say an overview of europe without any of the detail internal to the HRE and then an inset of the German states.