Link to butterfly images is broken

[extua]

The links to images of butterflies in the map popup is broken.

butterflies/server/index.html

Line 280 in 06abf39

var imageUrl = 'https://www.nhm.ac.uk/services/media-store/asset/' + item.image + '/contents/';

For example, this link to Gonepteryx rhamni rhamni returns a 503 Backend fetch failed error.
https://www.nhm.ac.uk/services/media-store/asset/1b2639e4863d7660da261b0220ed40fadd6b17d1/contents/preview