I'd echo [MENTION=6801204]Satyrn[/MENTION] on paint.net so you can take advantage of layers when doing your maps. While I don't use it for maps, I do use it for NPCs, monsters and scenes. Sometimes I'll grab an image, manipulate it and just throw the image into a word document so I can show my players a page. PowerPoint would work too of course, but I never have an exact sequence I want to show.
Or for what you need, just having clearly labeled layers you can remove would work.
Or for what you need, just having clearly labeled layers you can remove would work.