Bugfix/series cover not setting (#527)

* Fixed an issue where cover generation was failing on first add due to not checking correctly on First Volume.

API/Services/MetadataService.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
-using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
 using API.Comparators;
@@ -37,11 +36,6 @@ namespace API.Services
             _imageService = imageService;
         }
 
-        private static bool IsCoverImageSet(byte[] coverImage, bool forceUpdate = false)
-        {
-            return forceUpdate || HasCoverImage(coverImage);
-        }
-
         /// <summary>
         /// Determines whether an entity should regenerate cover image
         /// </summary>
@@ -104,7 +98,8 @@ namespace API.Services
         /// <param name="forceUpdate">Force updating cover image even if underlying file has not been modified or chapter already has a cover image</param>
         public void UpdateMetadata(Volume volume, bool forceUpdate)
         {
-            if (volume == null || !IsCoverImageSet(volume.CoverImage, forceUpdate)) return;
+            if (volume == null || !ShouldUpdateCoverImage(volume.CoverImage, null, forceUpdate
+                , false)) return;
 
             volume.Chapters ??= new List<Chapter>();
             var firstChapter = volume.Chapters.OrderBy(x => double.Parse(x.Number), _chapterSortComparer).FirstOrDefault();