ps2pdf --- This is a script to run ghostscript or gs, which you can install with Homebrew following the instructions from @luckman212. I think mine was installed by MacPorts, so that is could be an option if you don't use Homebrew. One issue for me was that default ps2pdf made a lot of extra whitespace around my image, apparently because default ghostscript assumes a full page size for the output PDF. Using a StackOverflow tip, I found that ps2pdf -dEPSCrop sizes the output PDF nicely, just like the result from Apple's ephemeral pstopdf command.