File Format - Open In vs Edit In

[dohearne]

If I use the Edit In option of LR Mobile (Healing) the return save to LR Mobile is as a png file. But if I Open In Photoshop Fix and do the identical Healing edit, when I save back to LR Mobile it saves as a jpeg. I do not understand this and what advantage if any that the png file might have?

[Keeptickin]

And how can we keep it as dng??