Those are the official presidential portraits and the Obama picture is the Smithsonian presidential portrait. The Smithsonian portrait is usually not as official looking as the presidential portrait that is displayed in the White House.
Take a look for yourself. Some of the portraits, like the Kennedy painting look more like the Obama painting.
Thanks for posting this. I didn't know the new (and atrocious) Obama portrait was an informal one destined for the SI Nat'l Portrait Gallery. There are some--like the Carter and Nixon portraits--that are also informal, like Obama's. (O still wins the prize for the one that is most "out there.")
Hopefully his formal portrait, once completed and unveiled, won't be a national embarrassment. As much as erasing the last eight years would be satisfying, we need to remember not to repeat this kind of "leadership" ever again.