Top photo: The Bund, Hong Kong. Photograph by John Thomson, 1868/1871. | Wellcome Collection
Bottom photo: The Bund, Hong Kong. Photograph, 1981, from a negative by John Thomson, 1868/1871. | Wellcome Collection
A bit confusing: both photos have the same title, and at first sight they look the same. But take a closer look and see the different piers. The upper photos shows Pedder's Wharf (1st generation) [c.1861-1871], the lower one obviously a different one: Pedder's Wharf (2nd generation) [c.1872-1886]. The first wharf was in line with Pedder Street, the second one a bit to the east.
To see this more clearly, the area of the piers was magnified in this photo:
I think the upper photo is from 1869, the lower one was taken when the new pier was constructed in late 1871 or early 1872.