Could you please help me with this? A bit of context:
Look at this painting. In the painting you can see a little girl. So, it is a painting of a girl. A famous painter painted it. So it is a painting ___ a famous painter.
I thought we should use "of" to show that the painting depicts the person, while "by" shows who painted it, but in the test it was "of" in both cases. Is "by" acceptable /correct or not in the latter case?.



This is a painting of a famous painter.
This is a painting by Vincent van Gogh.
– Thinkeye Mar 21 '18 at 14:22