I'm curious about the extra person in a lot of these images. In some, they're clearly disciples of the Yoga guru and paying obeisance, but in some others it looks like they're holding a spade[1] or (what looks like) washing clothes[2][3] or stoking a fire[4]. It could be just to add some variety and background to the image, but I wonder if there's more to it, perhaps something related to the Yoga asanas that are being depicted in each one.
I Think [2]may be someone grinding a food substance on a flat mortar and pestle style implement. Such things are still used in India and other parts of the world, and even Yogis still need to eat sometimes.
[1] https://the-public-domain-review.imgix.net/collections/hatha... [2] https://the-public-domain-review.imgix.net/collections/hatha... [3] https://the-public-domain-review.imgix.net/collections/hatha... [4] https://the-public-domain-review.imgix.net/collections/hatha...