private void CopyMainImages(IEnumerable <Entity> entities, string inputPath, string outputPath)
        {
            //build the mod input list
            var inputDirectories = StellarisDirectoryHelper
                                   .CreateCombinedList(StellarisDirectoryHelper, modDirectoryHelpers, Last)
                                   .Select(x => Path.Combine(x.Icons, inputPath)).ToList();

            // tech images
            ImageOutput.TransformAndOutputImages(inputDirectories, Path.Combine(outputRoot, outputPath), entities);
        }