Resizing Picture Dimensions on a Mac

in Windows, you could right click on a picture or photo and automatically get a few options for resizing, as well as custom settings. I can't find anything like that in iPhoto, or am I just missing it?

The easiest is to just import the image into iPhoto and export it with a new size.

I tried right clicking on an image and made an Automator workflow that resized one or more input images to a different folder for output.

There seems to also be an Apple script in the system that can do this. You need to add the icon to the menu bar and go to Script Editors Scripts > Image Manipulation > Resize. I didn't bother trying to run that so can't say how it works.