HELP! wife's sister sent me a nude?

So, the other day when I was out of town on a business trip I received a snapchat from my sister in law. She has snapchatted me before so I did not think much of it until I opened up the message and there she was standing seductively in some lingerie. I could not believe what I had seen. I did not respond, and I have no Idea how to handle this moving forward. I am hoping that this was an accident and I can just forget that it ever happened.

Should I tell my wife? I don't want to cause any problems between them, especially if it was an accident. Do I just talk to my sister in Law? How do I handle this situation? any help would be beneficial