I'm following through Jesse Freeman's Lynda course Unity 5 2D Essential Training. The exercise files contain sprites with transparency. Here's a screenshot of one such sprite on the trainers screen (sorry it's so small):
But here's how it looks in my scene in Unity 5.5.0F3:
I think that the sprite's alpha properties are set correctly, I have Alpha Source set to "Input Texture Alpha" and Alpha Is Transparency is checked:
When I open the PNG in PhotoShop the transparency is correctly set:
Why is the transparent area rendered as opaque in my sprite?