Looks like Google+ has been toying with photos that I uploaded to Blogger. They've created "Auto Awesome" photos and slide shows as a "gift" to me (and you, too, probably).
So somehow this photo that I posted and chose because it happened to just "be there" when I was trying to do a blog post from my phone, had been previously manipulated by Blogger/Google to have snowflakes. And there you have it.
UPDATE: After some Googling I find that this happens through the Google+ and I thought the App must be on my iPhone, but it is not available for the iPhone, so it must have been done through my Google+ account???? Apparently you can't actually control the final product, Google does it for you. Go figure.
Here is a video "gift" Google+ made from random photos from my various blogs: