The image you linked to was obviously created in order to show [someone] in a bad light, and I can't imagine that anyone wanting to do that would use typical photos rather than particularly bad-looking photos for that purpose.

This is the most salient conclusion. Photography is — among other things — the art of selectively promoting some visual evidence to the viewer's consciousness.

To put it differently: I suspect that "moral disgust" takes different forms on the left and on the right: on the left it's usually moral disapproval that has engendered disgust, and on the right it's usually disgust that has engendered moral disapproval.

I'm not so sure. For one thing, "the left" and "the right" are concepts far up the ladder of abstraction, whereas a lot of "moral disgust" seems to be trained System 1 responses. Here are some things that might elicit "moral disgust" responses by people with different trained responses:

• A parent and five-year-old child are in a store. The child picks up a toy from a shelf and does not put it back when the parent tells him to. The parent slaps the child on the face. The child drops the toy, begins quietly crying, and then puts it back on the shelf.
• A political leader holds a rally in which the symbols of his party and nation are presented alongside one another. In a speech, he denounces the opposition party as corrupted by global business elites.
• Two women sit on a park bench cuddling and kissing each other.
• An elderly man dies alone in a nursing-home bed. He hadn't seen his son or daughter in ten years. His death is not noticed by staff for twelve hours.
• Two fifteen-year-olds have sex. They use a condom, but it breaks. The young woman goes to the neighborhood pharmacy and buys an emergency contraceptive with her own money.
• A worker completes his federal tax forms and mails a check to the government. He feels proud to have completed a duty to his nation.
• A family finish dinner and throw away several portions-worth of uneaten food.
• In a city playground, a man is watching twin girls swing on the swings.
• A religious denomination, facing declining attendance, combines three parishes into two. They sell the now-abandoned third church building to a commercial developer. The developer has the sanctuary demolished and puts up a pirate-themed sports bar with scantily-clad waitresses. (Arrr.)
• Outside an open-air market in an affluent suburb, an elderly woman is sitting on the sidewalk with a sign asking for money to pay for food and medicine.
• An engineering company releases a product that is so successful, their competitors close up shop and lay off tens of thousands of workers.
• A singer performs on television wearing only a skimpy bikini printed with the national flag.
• A political leader orders a bombing run on a city block that contains both a terrorist headquarters and a pediatric clinic.
• A professor asks an undergraduate student to come to the professor's house for dinner. Later, they have sex.
• An artist uses her own bodily wastes as a medium to paint a representation of a religious figure, seals it in plastic, and exhibits it in a gallery.
• A business executive contemplates a report on the expected costs of cleaning up a polluted factory site and the likelihood of a successful lawsuit against her firm. She decides not to order the cleanup.
• A dark-skinned man who was raised Christian, and a light-skinned woman who was raised Muslim, meet at a social event and become romantically involved.
• A woman accused of murdering her two children is found not guilty and released. The judge cites the fact that a police officer on the case was found to have threatened the woman's neighbor to get the neighbor to testify.
• A man comes home from work and finds a note from his wife saying that she is out at her boyfriend's house and will be back around 7:30pm. When she gets home, her husband has prepared dinner for the two of them. Later, in bed, they watch the latest episode of My Little Pony: Friendship is Magic.