Leyster was a Dutch Golden Age painter. Arguably the first woman in the Haarlem Guild of St. Luke, almost all her work is from the years 1629 - 35, before she married and had children. She specialised in portrait-like genre scenes - and details from some of her music-related paintings are telling. Here is her 1630 painting, The Carousing Couple. Notice the very high third and fourth fingers, the extremely short bow, and the cap over the tip, illustrating an early method of fixing the hair (a simple knot in the hair fixed in a slot in the stick, covered by the cap).
Here is detail from another of her paintings, The Concert, from 1631-33, showing again this very "Italianate" bow hold -- interesting for northern Europe so early in the century, and once again demonstrating that too rigid a picture of playing-styles might be misleading. It's also probably worth observing that the (impossibly?) crooked bow calls into question the factual accuracy of the painting. Here the bow is a more normal length (approx. the length of the violin), and the attachment of the hair at the tip seems more modern.
... and now that we've established that Leyster was illustrating the Italian style, what about this detail-- probably from 1629, called either The Merry Company or The Merry Trio. In any case, note the remarkably straight bow, and the the thumb under the frog, French style! And again, a very short bow.