Tips for taking a good screenshot - briansd9/exile-diary GitHub Wiki

Zooming in (by scrolling the mousewheel forward) can help.
It's best to take the screenshot right after entering the map, but if it's not safe (monsters in sight, for instance) any time before you leave the area is OK.
The background doesn't have to be completely black, as long as the area name and level are readable.
Some samples of "good enough" screenshots: