Facebook Graph API - Object Insights for any Photo returns 0 for all Metrics

Using the Facebook Graph API I am able to retrieve data for a photo post - I can see the object likes and object comments which return data. So I know I have the correct ID for the photo.

However when I try to use object insights all the values returned are 0, which I know is not true via the insights dashboard on my account: http://ift.tt/g8FRpY{page name}/insights/

The query I am running is:

http://ift.tt/1Cei3Sz id}_{post id}/insights

Which I am doing via the API tool: http://ift.tt/jdBOke

If I try a status or a link, they return values.

Does anybody have any ideas?