In the same era, photos were taken of emigrants (who would be no more accessible to family members than the dead) and livestock (especially exceptional or prize-winning animals). All were predictable subjects of early photography -- especially given expense and long exposure times. The rise of photography also paralleled a surge of interest in the spirit world (see Neatorama's own article on Houdini) and reflected the then-prevalent understanding of death as both warning (against ignoble deeds) and encouragement (to experience life fully).

I fear I have to agree with Esta Griffiths; Zeon Santos' article reflects more personal bias than the understanding produced by credible research. It even suggests (by omission or ignorance) that post-mortem photography is a Victorian anomaly, rather than an ongoing practice (https://au.news.yahoo.com/thewest/a/24297810/putting-the-fun-back-into-funerals/).