profile-cards has an invalid image uri
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I am Quang. In "profile-cards" example, Jackie profile image i invalid.

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| Requesting a new feature
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**Proposal/Feature-request:**

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| Reporting a bug or issue
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**Expected behavior:**
In sketchapp, it should show Jackie profile image.

**Observed behavior:**
Sketchapp shows nothing, except a RED rectangle.
In main.js, this uri seems invalid
https://pbs.twimg.com/profile_images/756488692135526400/JUCawBiW_400x400.jpg

**How to reproduce:**

**Sketch version:**

**Please attach screenshots, a zip file of your project, and/or a link to your github project**
![image](https://user-images.githubusercontent.com/1145845/27990877-370a0f3c-648f-11e7-9a9b-5026e2a6cdb7.png)

Thanks,
