There's no trouble with my machine being able to handle a large image.

I actually went the GIMP route after, er... "demoing" CC3. The redraw rate on that program when you have just a few simple style sheet effects active is ridiculously slow. And really, the only thing that appealed to me about CC3 was all the fractal line/poly options, which makes it easy to make realistic-looking land. But the "not-so-random coastlines" method demoed elsewhere here eliminates my need for that, and the program can make much prettier maps at the expense of not being easily scaled. But I have Inkscape for that, don't I?