import 'package:custom_image_picker/custom_image_picker.dart';

List<PhoneAlbum> albums = [];
final customImagePicker = CustomImagePicker();
customImagePicker.getAllImages(callback: (retrievedAlbums) {
     albums = retrievedAlbums;
});

class PhoneAlbum {
  final String id;
  final String name;
  final String coverUri;
  final int photosCount;

  PhoneAlbum(this.id, this.name, this.coverUri, this.photosCount);

  ...
}

List<PhonePhoto> imagesOfAlbum = [];
final customImagePicker = CustomImagePicker();
 customImagePicker.getPhotosOfAlbum(
     albumID, // The id of the album you want to retrieve the images for
     page: page, // The page number defaults to '1', in each page the library returns 50 images of the album
     callback: (images) {
         imagesOfAlbum.addAll(images);
     },
   );

class PhoneAlbum {
  final String id;
  final String albumName;
  final String photoUri;

  PhonePhoto(this.id, this.albumName, this.photoUri);

  ...
}