Many thanks to Batch Resize Images Quickly in the OS X Terminal for giving me a quick and perfectly adequate way to make thumbnails for a web page from 32 photos:
sips -Z 256 *.jpg
Destructive! Work on copies.
Sven Dahlstrand That's such a clever one-liner. To everyone following along at home: keep copies of your originals as this is a destructive action.
Miraz Jordan @sod I first tried some Automator actions and the results were terrible. This command did a nice job.
Miraz Jordan @sod Yes, indeedy! I didn't think to add this warning on my post. Thanks. Now updated!