skip image when data not exists

DataManager.cs

@@ -53,14 +53,7 @@ namespace ImgGen
             else
             {
                 Console.WriteLine($"Card {code} not found!");
-                Data data = new Data
-                {
-                    code = code,
-                    name = "???",
-                    text = "???"
-                };
-                return data;
-            }
+                return null;
         }
 
         public static string FormatCardDesc(string r)
@@ -91,4 +84,3 @@ namespace ImgGen
         }
     }
 }
-

ImageManager.cs

@@ -149,6 +149,10 @@ namespace ImgGen
         public Bitmap GetImage(int code)
         {
             Data data = DataManager.GetData(code);
+            if (data == null)
+            {
+                return null;
+            }
             return DrawCard(data);
         }