She had some formal art training and painted for much of her adult life. From what I've read about her, it seems that most of the paintings she made were for herself; she didn't have to paint to make a living.
Given when she lived and who she associated with (artist Duncan Grant and artist / art critic Roger Fry, among others), she was swept up in modernism, especially 1910-20. By the late 1930s she pulled back and made more conventionally representational paintings. I am not aware that she painted abstractions.
The Guardian piece linked above makes her out to be far more than she was, if the images below are any evidence.
She painted several pictures of people where faces were either lightly indicated or simply rendered as colored blobs. My conjecture is that she (or one of her friends, likely Roger Fry) thought that including facial detail would make faces the painting's focus, whereas a blank face would allow viewers to contemplate the image in "formal" terms -- color, composition, and such.
A Cézanne-like treatment of Vanessa's sister, the writer Virginia Woolf.
More faceless subjects, thinly painted.
The biographer before he gained fame and wealth.
This is the only Cubist-inspired portrait I'm aware of, though others might have been destroyed in a World War 2 air raid.
The pink face and pink wall provide a modernist version of a Coles Phillips illustration.
Accurate anatomy, linear perspective, scale and other attributes are sacrificed to the gods of modernism.
Here she retreats a little from extreme modernism. Drawing is more accurate, but brushwork remains dabby.
Perspective is ignored, and the colors give this a whiff of Henri Matisse.
This is much more representational, but the brushwork remains haphazard.
Virginia Woolf's husband, perhaps doing his obsession, the finances for the Hogarth Press.
A postwar painting with even more compromises with representationalism, though it retains a modernist feel.
Done not long before her death.