I've created an automator file for batch importing folders of jpgs to PowerPoint 2011 for Mac. Instead of loading your jpgs to your PPT 1-by-1, the tool will load all of the images in 1 step. The automated process also resizes the images to screen-sized within the PPT slides. You may
download the file here.
See this 30-second video tutorial to learn how to use the tool:
http://screencast.com/t/LCiVLfOE