The MovingAI Benchmark Database is one of the most famous collections of maps for benchmark on pathfinding algorithms. I use it a lot during my work, it is useful to test an algorithm over a lot of real-world game maps. The consequence is that I developed a lot of tools to work with the map format of the MovingAI database.
The last of these tools is a straightforward Python script to convert images into maps in the MovingAI format. It is useful when you want to quickly develop some test maps.
Nothing fancy, but it may be useful to some of you. I hope. :) I will add some functionality in the future (such support for water, swamps and custom tiles).
Ah! And if you want, you can convert the .map file into JSON with this other tool. :)