Known Lands - Continental Map

[kerub]

Cropping only masks the selected visible part of the image away. It is completely reversible but can be made permanent to reduce file size (at least in the newer versions of Photoshop). All layers will be left intact. You simply crop your picture and then "Save as...". This way you basically get a copy of your original file with everything in it.

But be advised that when you really want to go deeper on every part of the map (from continental to city as you said) you will need a gigantic original image to maintain quality. Simply blowing things up looks bad. I would say at minimum 10000 pixels wide, even more depending on the scale of your original map and how deep you really want to go.