Super imposing two images

[Krikor]

• Having two layers, the one on the map below and the other on the top. Zoom in/out to taste (use Scale Tool - Shift + S)
  

• With the Select by Color Tool (Shift + C) click on a black part of the map.
  

• With the selection still active, select the layer with the other image and click the right mouse button:
  

• Add Alpha Channel then click again - Add Layer Mask - check the Selection option.