add gif image support

MediaBrowser.Controller/Entities/BaseItem.cs

@@ -1,5 +1,4 @@
 using MediaBrowser.Common.Extensions;
-using MediaBrowser.Common.IO;
 using MediaBrowser.Controller.Channels;
 using MediaBrowser.Controller.Collections;
 using MediaBrowser.Controller.Configuration;
@@ -46,7 +45,7 @@ namespace MediaBrowser.Controller.Entities
         /// <summary>
         /// The supported image extensions
         /// </summary>
-        public static readonly string[] SupportedImageExtensions = { ".png", ".jpg", ".jpeg", ".tbn" };
+        public static readonly string[] SupportedImageExtensions = { ".png", ".jpg", ".jpeg", ".tbn", ".gif" };
 
         public static readonly List<string> SupportedImageExtensionsList = SupportedImageExtensions.ToList();