public async Task AddImages(IEnumerable <string> filePathes) { var newVMs = new List <ImageViewModel>(); foreach (var filePath in filePathes) { if (Contains(filePath)) { continue; } var image = new ImageModel(filePath); _collection.Add(image); var vm = ViewModelFactory.CreateImageViewModel(image); Add(vm); newVMs.Add(vm); } foreach (var imageViewModel in newVMs) { await imageViewModel.LoadPreviewImage().ConfigureAwait(true); } }