Board Thread:Questions and Answers/@comment-24540596-20140212233512/@comment-1789156-20140212233911

All custom flags and maps are made by the community. I personally use Paint.net for PNG files, and inskscape for SVG files. If you have an idea for a cool flag or map I'm sure a member of the community would be happy to help you.

If you need a blank map, I recommend looking here. That is the list of blank maps used by Wikipedia and is a great source for finding a base map.

I hope that helps to get you started.