\hbox{
  \hfil
  \picture{../photos/2019-12-13-3.jpg}{An antlion in the inter-trial holding containers with native sand}{3in}
  \hfil
  \picture{../photos/2019-12-13-3.jpg}{THIS PICTURE SHOULD NOT BE HERE}{3in}
  \hfil
  \picture{../photos/c.jpg}{All of the antlion holding containers in the corner}{3in}
}