modify

Editor/Postprocessor/Atlas/EditorSpriteSaveInfo.cs

@@ -240,11 +240,24 @@ public static class EditorSpriteSaveInfo
 
     private static List<Sprite> LoadValidSprites(string atlasName)
     {
-        return _atlasMap[atlasName]
-            .Where(File.Exists)
-            .Select(p => AssetDatabase.LoadAssetAtPath<Sprite>(p))
-            .Where(s => s != null)
-            .ToList();
+        if (_atlasMap.TryGetValue(atlasName, out List<string> spriteList))
+        {
+            var allSprites = new List<Sprite>();
+
+            foreach (var assetPath in spriteList.Where(File.Exists))
+            {
+                // 加载所有子图
+                var sprites = AssetDatabase.LoadAllAssetsAtPath(assetPath)
+                    .OfType<Sprite>()
+                    .Where(s => s != null)
+                    .ToArray();
+
+                allSprites.AddRange(sprites);
+            }
+
+            return allSprites;
+        }
+        return new List<Sprite>();
     }
 
 #if UNITY_2022_1_OR_NEWER