OLL thumbnails are not included in API response

[mbertrand]

Steps to Reproduce

Query the Open Learning Library API to retrieve course/run information .

Expected Behavior

The API response contains thumbnail URL's in the response (particularly, the image field).

Actual Behavior

The image field is always null.

The API is currently unavailable due to expired credentials, if the problem persists after regaining access, we have two options:

a) Ask whoever is in charge of the API to make sure the image field is not blank.
b) Modify our code to examine the course URL page and try to parse an image out of the HTML