Skip missing images when creating collages (#14344)

* Skip missing images when creating collages

src/Jellyfin.Drawing.Skia/SkiaHelper.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.IO;
 using SkiaSharp;
 
 namespace Jellyfin.Drawing.Skia;
@@ -27,12 +28,17 @@ public static class SkiaHelper
                 currentIndex = 0;
             }
 
-            SKBitmap? bitmap = skiaEncoder.Decode(paths[currentIndex], false, null, out _);
-
+            var imagePath = paths[currentIndex];
             imagesTested[currentIndex] = 0;
-
             currentIndex++;
 
+            if (!Path.Exists(imagePath))
+            {
+                continue;
+            }
+
+            SKBitmap? bitmap = skiaEncoder.Decode(imagePath, false, null, out _);
+
             if (bitmap is not null)
             {
                 newIndex = currentIndex;