Those are fine if you want to adjust contrast and tone but to turn it into something like this would require more control over you images. I shoot mainly in RAW these days, after which I send that into Lightroom and do what I need with it. The nice thing about the workflow is that Lightroom offers non destructive editing of the master file, which is great.
Once you are happy with the final result, you export it out as a PNG or JPG. I don't bother much with DNG for now as it takes up too much space on my HD.
I like DNG files as a means of perserving my photos in digital, and PNG as a second choice as it can be viewed on a standard web browser. DNG is not user friendly as you need a photo editing app that can open these files.
DNG's main advantage is that you are holding all the image details within the pix, and the data is uncompressed. You can do the dame with PNG files in 16 bit format but that's a little hard to muster if you have limited space on your HD. Ever since digital became the mainstay, HD capacities have grown and no matter how much it has grown, it's still not enough. Flickr may have rescued the day with a 1TB limit. But sadly, that's not going to last if you store hundreds of megapixels every day on your account. You still need to generate those files and have a copy stored up somewhere at home instead of having it uploaded up to the cloud. Flickr accepts files in PNG.
There is another player, 500px.com, which also gives you a gallery of sorts but they are more conservative by allowing you a limited number of uploads and they don't accept PNG files. So what's the best workflow? For the time being, PNG files are way better for me and Flickr has it.
Once you have a lossy file in a compressed JPG format, it is just not worth saving up to the cloud as a back up. Why bother? Sharing is low res JPG anyway so if all you ever do is that odd FB photo which you post to your timeline, then stick to JPG.
If you really need a backup space, then start at Flickr, save your files in PNG. Need more space? Then set up another account. 1TB is a probably good for a year if you shoot often and want to back up to the cloud.
What about other Cloud Services?
Been there, done that. Again, not worth it. You can save your PNG files to Dropbox or Box.net but those service don't give you much space. The most I ever got from Dropbox was 50GB. That's a paltry sum compared with Flickr. In fact, that is all that cloud services want to give you for a limited time. Anymore than that, you'd have to pay.