They make it look as though Vivian only got the idea to go through Anna's social media time lines after Neff tells her that Anna constantly took selfies in the 12 George hotel but that would of course be the very first thing a journalist would do.
After talking to Anna's friends and acquaintances, who paint a very inconsistent picture of her, Vivian throws a hodgepodge of Anna's Instagram photos from the past five years on her nursery wall. They, too, look wildly inconsistent, which makes it look as though Anna was constantly changing her appearance and backstory, reinforcing the impression of Anna as a criminal scam artist. However, social media postings are posted one after the other, which is why the sum total is called a "time line". A journalist would of course structure all this in sequence, at least initially, in order to discover periods and developments.
At about 12:00 in, when Vivian is writing her letter to Anna, icons for Cinema 4D and Adobe After Effects can be seen in the toolbar at the bottom of her computer screen. It's highly unlikely a reporter would have professional grade 3D and 2D animation software (made for animators and graphic designers) on her work computer.