The Hathayoga Project "resources" page points to the Hartsuiker Archive of 1900 photos at the British Library. This is an amazing resource. But the
British Museum link has stopped working. Using keywords it is possible to find a lot of the Hartsuiker images, but only in a kind of haphazard manner.
Does anybody here know whether the BL has a (new?) "Hartsuiker Digital Collection" page that showcases the collection properly? I can't find one.