fixed image providers from running everytime against collection folders

MediaBrowser.Controller/Entities/BaseItem.cs

@@ -905,7 +905,6 @@ namespace MediaBrowser.Controller.Entities
             if (changed || forceSave || themeSongsChanged || themeVideosChanged || localTrailersChanged)
             {
                 cancellationToken.ThrowIfCancellationRequested();
-
                 await LibraryManager.UpdateItem(this, cancellationToken).ConfigureAwait(false);
             }
 
@@ -1506,7 +1505,7 @@ namespace MediaBrowser.Controller.Entities
             }
 
             // Refresh metadata
-            return RefreshMetadata(CancellationToken.None);
+            return RefreshMetadata(CancellationToken.None, forceSave: true);
         }
     }
 }

MediaBrowser.Controller/Entities/CollectionFolder.cs

@@ -15,7 +15,7 @@ namespace MediaBrowser.Controller.Entities
     /// Specialized Folder class that points to a subset of the physical folders in the system.
     /// It is created from the user-specific folders within the system root
     /// </summary>
-    public class CollectionFolder : Folder, ICollectionFolder, IByReferenceItem
+    public class CollectionFolder : Folder, ICollectionFolder
     {
         /// <summary>
         /// Gets a value indicating whether this instance is virtual folder.

MediaBrowser.Controller/Entities/Folder.cs

@@ -760,7 +760,7 @@ namespace MediaBrowser.Controller.Entities
                     var child = currentTuple.Item1;
 
                     //refresh it
-                    await child.RefreshMetadata(cancellationToken, resetResolveArgs: child.IsFolder).ConfigureAwait(false);
+                    await child.RefreshMetadata(cancellationToken, resetResolveArgs: child.IsFolder, forceSave: currentTuple.Item2).ConfigureAwait(false);
 
                     // Refresh children if a folder and the item changed or recursive is set to true
                     var refreshChildren = child.IsFolder && (currentTuple.Item2 || (recursive.HasValue && recursive.Value));

MediaBrowser.Controller/Providers/ImagesByNameProvider.cs

@@ -126,6 +126,7 @@ namespace MediaBrowser.Controller.Providers
             }
 
             data.Data = ConfigurationManager.ApplicationPaths.ItemsByNamePath.GetMD5();
+            SetLastRefreshed(item, DateTime.UtcNow);
      
             return result;
         }

MediaBrowser.Server.Implementations/Library/LibraryManager.cs

@@ -269,16 +269,16 @@ namespace MediaBrowser.Server.Implementations.Library
             // Need to use DistinctBy Id because there could be multiple instances with the same id
             // due to sharing the default library
             var userRootFolders = _userManager.Users.Select(i => i.RootFolder)
-                .DistinctBy(i => i.Id)
+                .Distinct()
                 .ToList();
 
             items.AddRange(userRootFolders);
 
             // Get all user collection folders
+            // Skip BasePluginFolders because we already got them from RootFolder.RecursiveChildren
             var userFolders =
-                _userManager.Users.SelectMany(i => i.RootFolder.Children)
+                userRootFolders.SelectMany(i => i.Children)
                             .Where(i => !(i is BasePluginFolder))
-                            .DistinctBy(i => i.Id)
                             .ToList();
 
             items.AddRange(userFolders);