For further reference [this class](https://github.com/jclouds/jclouds/blob/master/compute/src/main/java/org/jclouds/compute/strategy/impl/ReturnCredentialsBoundToImage.java) is the one that populates the default credentials to the images (you don't have to worry about that in the `ImageToImage` function, and [this is the one](https://github.com/jclouds/jclouds/blob/master/compute/src/main/java/org/jclouds/compute/config/BaseComputeServiceContextModule.java#L94-L95) that provides the default values, if no credentials are present, reading the value of the mentioned property.