I know here in the US, to show a photo of a deceased person in their casket would be in bad taste and disrespectful, but I have been doing some reading. I know very little about Puerto Rico and its customs. But in some of the reading I have been doing in order to try to better acquaint myself with the Latin culture I found the following.
One custom that does differ in the Latin American culture, as compared to other cultures, is the use of photography of the deceased during parts of the funeral rite. A family member explained that the pictures were used as a marker to preserve the death as an important historical event in the heritage of the family and also as an acknowledgment of the Rite of Passage for the deceased.
http://www.funeralwise.com/customs/cross-cultural-funerals
In the olden days photographing the dead, sometimes in odd, lifelike poses was not uncommon even here in the states.
I am chalking it up to cultural differences.