In the Snapchat page (https://support.snapchat.com/ca/incompatible) you can vote for Windows Phone. If we all make our vote, I think Snapchat's people are going to have reasons to create an official app.
Let's vote!
Let's vote!
Ok I checked Windows phone. But what next???? WTF???
Though I heard a rumor that Snapchat is waiting for GDR3. because of the screenshot issue apparently