Grails Facebook-sdk publish image to user wall gives File Not Found Error



I am using the grails facebook-sdk plugin to connect and post to facebook.

To publish a message to a user's wall I use:

def publishMessageResponse = facebookClient.publish("me/feed", [message:"RestFB test"])

This works fine, but I want to post an image to a specific album of the user. The documentation says that it should work with:

def publishPhotoResponse = facebookClient.publishFile("me/photos", [message, "Test cat"], "/cat.png")

But I alway get a "File not found" error. The image I have is stored in a data base and can be retrieved by getting the url to the image.

Knowing the url of the image, how can I post this image to a specific user photo album? How can I create a new Album?