screenshot 2starfish for og:image

<img width="820" alt="XX" src="https://user-images.githubusercontent.com/949985/50261022-81a19d00-03bf-11e9-996e-caeab68024c4.png">

```html
<meta property="og:image" content="https://user-images.githubusercontent.com/949985/50261022-81a19d00-03bf-11e9-996e-caeab68024c4.png">
<meta property="og:image:alt" content="XX">
```
