IMO 2016, Hong Kong, the winning team of the US (including Po-Shen and Alex Zhai):

IMO 2016, Hong Kong, the US and South Korean teams:

MOP 2016 Black group (which includes the 6 members of the US IMO team, 1 member of the Canadian IMO, 2 members of the IMO Singapore team, 1 member of the Australian IMO team, and 1 member of the Hungarian IMO team):

MOP 2016 Blue group (which includes 2 members of the Canadian IMO team):

MOP 2016 Red 1 group:

MOP 2016 Red 2 group:

MOP 2015 Black group (which includes the 6 members of the US IMO team and 2 members of the Canadian IMO team):

MOP 2015 Blue group:

MOP 2015 one of the Red groups:

MOP 2015 one of the Red groups:

With the students participating in the Olympiad Training Program organized by the Ari de Sa high school in Fortalza (Brazil) in May 2015 (including the 6 members of the Brazilian IMO team):

With the US IMO team in 2014 in Cape Town, South Africa:

MOP 2014 Black group (which includes the 6 members of the US team and 3 members of the Canadian team):

MOP 2014 Blue group:

MOP 2014 Green group:

MOP 2014 Red group:

MOP 2013 Black group (which includes the 6 members of the US team):

MOP 2013 Blue group:

MOP 2013 Red groups:

Brazilian IMO Team 2013:

Brazilian IMO training, Grupo I:

Brazilian IMO training, Grupo II:

MOP 2012 Black group (which includes the 6 members of the US team):

MOP 2012 Blue group:

MOP 2012 Green group:

MOP 2012 Red group:

MOP 2012 Grading the TSTSTSTSTSTSTS:

MOP 2012 Grading the TSTSTS (everybody very tired):

Awesome Math 2012, Dallas:

An image with the leader (me, left), deputy leader (Zuming, right) and five of the

six members of the team that won the Romanian Masters in Mathematics in 2011:

The participants in the Brazilian Math Olympiad program 2011:
(including the 6 members of the IMO team)

Grading the US Math Olympiad with Zuming Feng, Melanie Wood, and Elgin Johnston:

In 2008 in Madrid, with the six members of the US IMO team, as well as Zuming Feng, Ian Le, and Steve Dunbar: