Be VERY careful with huge maps in Realm Works. Those maps explode in size very quickly, and we need to operate with multiple layers for those maps in order to handle all the pins and reveal regions. If you create a 4000x3000 map, you will potentially run into problems with Realm Works, and you'll we warned if you try to use a map that may be problematic.
In general, for computer display of maps, you only need a fraction of the resolution that's need for printing maps. When printing, you definitely want at least 300dpi, but for screen display 72dpi is typically plenty. Since Realm Works is about screen display and not printing, the much lower resolution is all you need, and going 300dpi down to 75dpi is SIXTEEN times smaller in overall image size (four times four).
Please keep this in mind when creating maps for use within Realm Works. If you need higher resolution for zooming in, generate a larger map at lower resolution for a large area and then create multiple smaller maps for different regions that are at a higher resolution. You can then link everything together smoothly within Realm Works and have everything work nicely.
Hope this helps!
