The library

Some of these pages, due to their nature as archives of historical artifacts, contain material that is now rightfully considered outdated and harmful. In those cases, it was included by the curators for historical transparency (see here the BHL's statement on this matter). While these images are a very small minority of the ones in these archives, they can still be upsetting to see.
I will list below the albums which contain harmful content as I come across them, but if you'd understandably prefer to stay safe, I recommend you browse by albums and avoid the ones focused on 19th-early 20th century pop culture and anthropology.
Elusive Muse: the "Ruckus" album (page 1) contains antiblack imagery
British Library: the "children's books" section includes scans from "My Little Chinese Book", of which some pages depict negative stereotypes of Chinese people