I'd like to be able to update the "title" and "subtitle" fields so that when participants enter, these display as more specific titles. For example "title" would display as "pet name" and "subtitle" would display as "city." How can I do that?
You can not rename our default fields. But you could use our Request additional image uploader information feature which is available in the advanced step when creating a photo contest. All custom fields can be public or only visible to admins. If you make them public, the fields become visible in the description.