SMW castle GFX are a default tileset on SMBX. Look under the SMW tab in Blocks while in the level editor. The castle GFX are of course under "Castle". If you are looking for any re-colours download the Community GFX Pack (Part 2 for SMW) or Red Yoshi's GFX.
Anyway, please just look harder next time though. It's kind of sad you had to waste people's time by asking a question like this, even if you are serious. If you are posting this as a joke it's really not funny and you should really cut it out.
<TheKingOfBoos> I don't speak non-american, shadowstar, I have no idea how hot that is
<Kogasa> it's like 92-93 in patriot units
<Merve> TKOB for next mod Support the GGP! Put this in your signature!