add mediumType attribute in ThumbnailProvider

example/lib/main.dart

@@ -181,16 +181,17 @@ class CollectionPageState extends State<CollectionPage> {
           crossAxisSpacing: 1.0,
           children: <Widget>[
             ...?_media?.map(
-              (media) => GestureDetector(
-                onTap: () => Navigator.of(context).push(
-                    MaterialPageRoute(builder: (context) => ViewerPage(media))),
+              (medium) => GestureDetector(
+                onTap: () => Navigator.of(context).push(MaterialPageRoute(
+                    builder: (context) => ViewerPage(medium))),
                 child: Container(
                   color: Colors.grey[300],
                   child: FadeInImage(
                     fit: BoxFit.cover,
                     placeholder: MemoryImage(kTransparentImage),
                     image: ThumbnailProvider(
-                      mediumId: media.id,
+                      mediumId: medium.id,
+                      mediumType: medium.mediumType,
                       highQuality: true,
                     ),
                   ),

lib/src/image_providers/thumbnail_provider.dart

@@ -4,12 +4,14 @@ part of photogallery;
 class ThumbnailProvider extends ImageProvider<ThumbnailProvider> {
   const ThumbnailProvider({
     @required this.mediumId,
+    this.mediumType,
     this.height,
     this.width,
     this.highQuality,
   }) : assert(mediumId != null);
 
   final String mediumId;
+  final MediumType mediumType;
   final int height;
   final int width;
   final bool highQuality;
@@ -30,6 +32,7 @@ class ThumbnailProvider extends ImageProvider<ThumbnailProvider> {
     assert(key == this);
     final bytes = await PhotoGallery.getThumbnail(
       mediumId: mediumId,
+      mediumType: mediumType,
       height: height,
       width: width,
       highQuality: highQuality,