Make sure 'fit' variable is an int for thumbnails

Ghost User
2017-06-28T19:54:42+02:00

Closes #428

#### Previous behaviour
Steps to reproduce:

1. Upload 1024h768w photo
2. Look up thumbnail
3. It's cropped

#### New behaviour
Steps to validate that it works:

1. Upload 1024h768w photo
2. Look up thumbnail
3. It's been resized