There's also a really nice online generator for those who don't understand how to find coordinates/are lazy. :D It's fairly simple; green plus sign means add an area, red minus means remove the area. You can choose rectangle, circle, or polygon, and paste the links for each in.
It does assign a random number for the map's ID/name, and you have to add titles for the links manually as far as I can tell, but it saves me a little time vs. paint or Image Ready.