EXIF thumbnail resolution is shown as resolution in "Details"

Example file: [Dropbox](https://dl.dropboxusercontent.com/u/13766493/shared/leafpic/IMG_20160713_241146372.jpg)

```
exif:ExifImageLength: 3120
exif:ExifImageWidth: 4160
exif:ImageLength: 384
exif:ImageWidth: 512
```

v0.4

![screenshot_2016-07-13-00-12-16](https://cloud.githubusercontent.com/assets/5863551/16784296/bfe37198-4890-11e6-892a-5e2944ea1760.png)
