Google slides
Part of your Google Apps for Education account. Images only, no audio.

Garageband is an application found on all MacBooks. Create a podcast with audio and still images.
http://www.biteslide.com/
Keynote is an application found on all student MacBooks.
Add images, record audio and embed into slide.
Screencasting using QuickTime
Audio recording using Quicktime, an application found on all MacBooks. 
https://narrable.com/
https://littlebirdtales.com