The definition under which u-photo became a draft property was one or more photos that is/are considered the primary content of the entry, unless there is a p-location h-card, which is still considered a "checkin" (i.e. with a photo). Otherwise the presence of a u-photo means the name of the entry should be interpreted as a caption on the photo, and the summary/content should be interpreted as a description of the photo.

However, this definition is not precise enough and needs to be refreshed before this becomes a stable property. There must be two publishers and two consumers consistent with the refreshed definition.

This definition needs to define what a multiphoto post is, specifically what multiple u-photo properties in an entry indicate. Bridgy, for example, in consuming h-entry to POSSE to Twitter, includes only the first four u-photo properties it finds, as that is Twitter's limit.

The final issue that has to be covered, the relationship of u-photo and its ilk to e-content, is open for discussion in #23