diff --git a/src/genworld_gui.cpp b/src/genworld_gui.cpp
--- a/src/genworld_gui.cpp
+++ b/src/genworld_gui.cpp
@@ -833,7 +833,7 @@ static void _ShowGenerateLandscape(Gener
 
 	if (mode == GLWM_HEIGHTMAP) {
 		/* If the function returns negative, it means there was a problem loading the heightmap */
-		if (!GetHeightmapDimensions(_file_to_saveload.name, &x, &y)) return;
+		if (!GetHeightmapDimensions(_file_to_saveload.detail_ftype, _file_to_saveload.name, &x, &y)) return;
 	}
 
 	WindowDesc *desc = (mode == GLWM_HEIGHTMAP) ? &_heightmap_load_desc : &_generate_landscape_desc;