Vincent in Arles
(1888)
 

Gauguin arrived in Arles on 23 October and, in November, he and Vincent painted together. Gauguin depicted Van Gogh in his The Painter of Sunflowers; Van Gogh painted pictures from memory, following Gauguin's suggestion. Among these "imaginative" paintings is Memory of the Garden at Etten.
Their first joint outdoor venture was at the Alyscamps, when they produced the pendants Les Alyscamps. The single painting Gauguin completed during his visit was his portrait of Van Gogh.
After a couple of weeks their relationship began to deteriorate; Van Gogh admired Gauguin and wanted to be treated as his equal, but Gauguin was arrogant and domineering, which frustrated Van Gogh. They often quarrelled; Van Gogh increasingly feared that Gauguin was going to desert him, and the situation, which Van Gogh described as one of "excessive tension", rapidly headed towards a crisis point leading to the mutilation of his ear.
https://en.wikipedia.org/wiki/Vincent_van_Gogh

Paul Gauguin - Van Gogh Painting Sunflowers
1888
Oil on jute
73 x 91 cm
Amsterdam: Van Gogh Museum
https://www.vangoghmuseum.nl/en/collection/s0225V1962

Was Van Gogh really painting a vase of sunflowers when his friend Gauguin produced this portrait of him? No, he can’t have been: it was December and far too late in the year for sunflowers. But it’s quite probable that Van Gogh painted a copy of one of his own sunflower pictures around this time. The landscape in the background is also fictional: unlike Van Gogh, Gauguin liked to work from his imagination. They often argued about this. This painting refers to their disagreement.
Later, Van Gogh wrote about this portrait: ‘My face has lit up a lot since, but it was indeed me, extremely tired and charged with electricity as I was then.’

https://www.vangoghmuseum.nl/en/collection/s0225V1962

Portrait of Gauguin
December 1888
Oil on burlap on panel
38,2 x 33,8 cm
Amsterdam: Van Gogh Museum
https://www.vangoghmuseum.nl/en/collection/s0257V1962

Van Gogh painted his friend, the artist Paul Gauguin, in their studio in the Yellow House. He made this small portrait on jute – an unusual but inexpensive material. Gauguin had bought some in Arles for the two of them to use. The coarse structure of the cloth made painting difficult, so Van Gogh applied the paint thickly and opted for a strong red-green contrast.

https://www.vangoghmuseum.nl/en/collection/s0257V1962