Here is some information from Wikipedia about death photography, or post-mortem photography, which was very popular in the nineteenth century.

The invention of the daguerreotype in 1839 made portraiture much more commonplace, as many of those who were unable to afford the commission of a painted portrait could afford to sit for a photography session. This cheaper and quicker method also provided the middle class with a means for memorializing dead loved ones.

These photographs served less as a reminder of mortality than as a keepsake to remember the deceased. This was especially common with infants and young children; Victorian era childhood mortality rates were extremely high, and a post-mortem photograph might have been the only image of the child the family ever had. The later invention of the carte de visite, which allowed multiple prints to be made from a single negative, meant that copies of the image could be mailed to relatives.

The practice eventually peaked in popularity around the end of the 19th century and died out as "snapshot" photography became more commonplace, although a few examples of formal memorial portraits were still being produced well into the 20th century.

The earliest post-mortem photographs are usually close-ups of the face or shots of the full body and rarely include the coffin. The subject is usually depicted so as to seem in a deep sleep, or else arranged to appear more lifelike. Children were often shown in repose on a couch or in a crib, sometimes posed with a favorite toy or other plaything. It was not uncommon to photograph very young children with a family member, most frequently the mother. Adults were more commonly posed in chairs or even braced on specially-designed frames. Flowers were also a common prop in post-mortem photography of all types.

The effect of life was sometimes enhanced by either propping the subject's eyes open or painting pupils onto the photographic print, and many early images (especially tintypes and ambrotypes) have a rosy tint added to the cheeks of the corpse.

Later examples show less effort at a lifelike appearance, and often show the subject in a coffin. Some very late examples show the deceased in a coffin with a large group of funeral attendees; this type of photograph was especially popular in Europe and less common in the United States.

Post-mortem photography is still practiced in some areas of the world, such as Eastern Europe. Photographs, especially depicting persons who were considered to be very holy lying in their coffins are still circulated among faithful Eastern Catholic, Eastern Orthodox and Oriental Orthodox Christians.

A variation of the memorial portrait involves photographing the family with a shrine (usually including a living portrait) dedicated to the deceased.

Here are some examples of post-mortem photos in the nineteenth century. WARNING: Some of these images might be disturbing.