Image to Map

I have image like https://i.gyazo.com/1c0e7c11d87cc884040300f72b5b5fdd.png

How do I make full ready map from it ?

Try to get the tile set and recreate the map. There are online tools that can split images into tiles.

In theory you could write a routine to convert it into a map, but I don't think that would be very efficient.

You could also use the image as scrolling background and an invisible map on top, but the image looks rather large.

My humble opinion, create the map manually. Then you can extend it as you please