\hbox{
  \hskip 0pt plus .5fil
  \picture{../photos/a.jpg}{Part of the DNA barcoding process for species determination: concentrated mixture after chemicals, centrifuging, and crushing}{5in}
  \hfil
  \picture{../photos/code.png}{The code used to create Voronoi diagrams with SciPy and Matplotlib}{5in}
  \hskip 0pt plus .5fil
}