I am trying to get the thumbnail for an image that has been posted as a file to the chatter. I have been able to do this for a User Profile image by sending &oauth_token=(my oauth token) as a query parameter, but cannot get it to work for the image thumbnails.
The Url i am trying to use is the renditionUrl240By180 property on the attachment item.
I have a url that looks like this:
When i send this i get the following response: INVALID_SESSION_ID Session expired or invalid