Sorry Charles but you lost me completely. (That's pretty lossy.) Please go back and re-read my post. I did software engineering for thirty years and I guarantee I'm not confusing lossless with jpeg compression. Yes, jpeg is lossy, sometimes very lossy. Nikon's lossless compression is lossless.
Oh, by the way, why do you think you need to upload 70 meg files? A very small crop can do the job.