It's supposed to be a small version of this.
But I see a young bride and groom kissing.[ETA: As it hasn't reverted on its own, I have now deleted the icon that wasn't mine and re-uploaded the correct picture. Thus the icon on this post has now reverted to the default.]
I noticed it had gone weird yesterday, but it's still not right today. I know coneycat had a similar problem a while ago, but strangely some people saw the right icon and some saw the interloper.
So what can you see in the icon for this post?
I see a grassy hill and blue sky
I see a young bride and groom kissing
I see something else entirely and will explain in the comments