tl;dr:
Peter Schauss at the University of Virginia says the wave packet is such a well-understood component of quantum theory that the findings of the new experiment are not surprising – but they do show that the researchers had a high degree of control over the processes used to cool and then precisely image the atoms.
I'm not entirely sure what they mean by having images of their waviness, because that is not how it works. You can not measure a quantum wave, because it isn't a "particle" wave but a wave-like distribution of mutually exclusive measurement outcomes. Taking a picture is the same as entangling yourself, which embeds you in the quantum wave function such that it describes all possible combinations of you ending up with every possible outcome.