Upfront: Offload S3 Support? Images doesn't load. (403)

Hi! It has been told somewhere that Offload S3 only supports WordPress' "built in image adding". Don't know what it should be called.. Anyway. Does Upfront support S3 offload and CloudFront? First it would be nice to know if it works, then if it does I would start thinking if I'm doing something wrong…

Thanks