If you right click on any user that is in your friends list, you can save a high quality photo of them. When the main ProfileView loads or the editProfile pane loads, it loads the full quality images associated with that users accounts. Even if internet technology is more superior than ever, it can still lag a bit.
Not sure what the consensus is.
Metadata may not be secured on this. We can find certain photographers associated with particular profile pictures of solid pod owners and what date the image was created.
If you upload an image to Facebook, I believe it recreates it. Essentially scrapping all of the old meta data.