diff --git a/Pixiview/Illust/ViewIllustPage.xaml.cs b/Pixiview/Illust/ViewIllustPage.xaml.cs
index 5fd0a75..d14b704 100644
--- a/Pixiview/Illust/ViewIllustPage.xaml.cs
+++ b/Pixiview/Illust/ViewIllustPage.xaml.cs
@@ -131,6 +131,7 @@ namespace Pixiview.Illust
 
             if (illust != null)
             {
+                IsAnimateSliderVisible = illust.IsAnimeVisible;
                 LoadIllust(illust);
             }
         }
@@ -352,9 +353,6 @@ namespace Pixiview.Illust
                 }
             }
 
-            var isAnime = illustItem.IllustType == IllustType.Anime;
-            IsAnimateSliderVisible = isAnime;
-
             Task.Run(() => DoLoadImage(0, true));
             if (items.Length > 1)
             {
@@ -363,7 +361,7 @@ namespace Pixiview.Illust
                     DoLoadImage(i);
                 });
             }
-            else if (isAnime)
+            else if (illustItem.IsAnimeVisible)
             {
                 // anime
                 ugoiraData = Stores.LoadIllustUgoiraData(illustItem.Id);
diff --git a/Pixiview/Utils/HttpUtility.cs b/Pixiview/Utils/HttpUtility.cs
index be7507b..96c3c72 100644
--- a/Pixiview/Utils/HttpUtility.cs
+++ b/Pixiview/Utils/HttpUtility.cs
@@ -299,7 +299,7 @@ namespace Pixiview.Utils
         private readonly IllustUgoiraBody ugoira;
         private readonly IllustDetailItem detailItem;
         private readonly ImageSource[] frames;
-        private readonly Timer timer;
+        private Timer timer;
         private int index = 0;
 
         public bool IsPlaying { get; private set; }
@@ -329,6 +329,7 @@ namespace Pixiview.Utils
             if (timer != null)
             {
                 timer.Dispose();
+                timer = null;
             }
         }
 
@@ -336,7 +337,7 @@ namespace Pixiview.Utils
         {
             lock (sync)
             {
-                if (IsPlaying == flag)
+                if (timer == null || IsPlaying == flag)
                 {
                     return;
                 }
@@ -409,7 +410,7 @@ namespace Pixiview.Utils
             index = i;
             lock (sync)
             {
-                if (IsPlaying)
+                if (timer != null && IsPlaying)
                 {
                     timer.Change(info.delay, Timeout.Infinite);
                 }