The following actions are included in a set called 'Resizing for Profs' which can be downloaded from the bottom of this page.
See Loading Photoshop Actions for step by step instructions on how to load these actions into your Photoshop actions palette.
Why these sizes for resizing images?
See our Theory of Using Digital Images slideshow.
How do I manually resize images?
See our Resizing in Photoshop guidelines.