In RM, a family is actually considered to be a person and spouse. For consistency, I use the Census individual fact for everyone in the household rather than having a mix of the individual and family facts.
Another option to consider would be to attach the Census individual fact to the head-of-household, then share the fact with the others in the household. Its limitation is that the GEDCOM standard doesn't support shared facts, so if you plan to export a GEDCOM for use with another program, you might want to avoid them.
How I have been doing it is as follows
Husband census family Source and add photograph
Wife automaticly adds census family and photograph
Child 1 census then use above source for it and photograph. Which I just discovered I can add a photograph to a source itself and not to each individual person from the gallery. That might make a diffrence as well.