Please help with sky fringing

Hi, after importing dng file into Camera raw 7, working on it, then clicking on - Open image - transporting image to Photoshop 6 to convert it into JPEG file ( the sky still looks good), then I close and save the file into My pictures. But when I open the file (with XNview), the sky looks terrible, not sure what the correct English term is, perhaps fringing, so I am including an example. Also how do I keep the original dng file? After sending the image to Photoshop, dng file after the post processing is saved, whereas I would like to keep the original dng file. Please advise how to avoid this, thank you Danny.