Daniel Kennedy provided the original file, phs_iteration_schematic.svg. This can be used to generate the html documentation. Bill Sacks then converted it to pdf using Inkscape (simply using "save as" and saving it as a pdf); the pdf is needed when generating a pdf (since latexpdf cannot use svg files). Note that the figure is referenced in the rst as phs_iteration_schematic.*; each builder then uses the appropriate file (svg or pdf as needed).