Upload & Sell: On
Use Lightroom. There are export modules to export a jpeg directly to Smugmug or flickr, and others. Just select the edited images you want, set the size you want to export, and its is very slick.
BTW, it is recommended that you use a max of 75% for export to Smugmug.
He has Aperture 3 already and probably doesn't want to change. I wouldn't (tried it and didn't care for the LR interface). And, like LR, Aperture has free plugins for auto export/resize to all the popular upload sites like Smugmug, FB, Flickr, etc. Actually FB & Flickr were already installed in my version of Aperture and are seen as icons on the left top.
Here's Apple "official" page but there are many off-site sources for Aperture plugins.