The traditional Worldcon Chairs Photo Session this year was right after the WSFS Business Meeting, the better to catch past, present, and future Worldcon chairs in their native environment and before they scattered to the winds on Sunday. (Besides, there's rarely been sufficient room at the Old Pharts Party for the photo.) After everyone took photos, Lisa took this video, asking the Chairs to give their names and conventions for the historical record.
In answer to a question raised on one of the still photos of this session I saw, note that Tim Illingworth was co-chairman of Intersection for a time, although he was not one of the co-chairs at the convention itself. This is explained in a footnote to the Long List of Worldcons.