PPIE had it

PPIE is that Panama-Pacific International Exhibition of 1915 the book on which I was reviewing. It exhibited this peculiar painting by Laura Knight, named Self-Portrait:

 The picture above is taken from this book on PPIE history:

Wiki doesn't mention PPIE as the exhibition location for this particular painting:

Self Portrait with Nude

Self Portrait with Nude, 1913

In 1913 Knight made a painting that was a first for a woman artist, Self Portrait with Nude, showing herself painting a nude model, the artist Ella Naper.^[18] The painting is a complex, formal composition in a studio setting. Using mirrors, Knight painted herself and Naper as seen by someone entering the studio behind them both. As an art student Knight had not been permitted to directly paint nude models but, like all female art students in England at the time, was restricted to working from casts and copying existing drawings. Knight deeply resented this, and Self Portrait with Nude is a clear challenge, and reaction, to those rules.^[2][4]

The painting was first shown in 1913 at the Passmore Edwards Art Gallery in Newlyn, and was well received by both the local press and other artists. Although the Royal Academy rejected the painting for exhibition, it was shown at the International Society of Sculptors, Painters and Gravers in London, as The Model. The Daily Telegraph's critic called the painting "vulgar", and suggested that it "might quite appropriately have stayed in the artist's studio".^[2]

Despite this reaction, Knight continued to exhibit the painting throughout her career, and it continued to receive press criticism. After Knight's death the picture, now known simply as Self Portrait (1913), was purchased by the National Portrait Gallery, and is now considered both a key work in the story of female self-portraiture and as symbolic of wider female emancipation.^[2][19] In 2015, Simon Schama described the painting as a "masterpiece" and "incomparably, her greatest work, all at once conceptually complex, heroically independent, formally ingenious and lovingly sensual."^[6]

Both those ladies, Knight and Naper were extremely heroic at the time, sure. I like that Ella Naper a tidbit more, but it's just me.

PPIE exhibited plenty of other interesting artists and their works. 

E.g., some other works of one Nicholas Fechin who also exhibited at the PPIE:

not this one though:

Very touching allegory of California: singing peasants with oranges, Roman heraldic matrona with a spear, a bear sniffing flowers and berries.

View of the Arch of the Nations of the West, a painting by some Adolph Alexander [whatever]...