Keynote is an alternative to Microsoft PowerPoint. It has many advantages. Its handling of media files is much better. It produces very slick presentations. It has a number of useful export options - for example allowing you to export to an interactive QuickTime movie - complete with any buttons or 'hot spots' you set up in your presentation.

There is an easy way to make a series of slides in Keynote from a group of images in the Finder.

From the Finder, simply highlight the images you want to import to Keynote and drag them to the Navigator window along the left edge of the presentation. (You may have to set your View mode to Navigator (e.g. Keynote » View » Navigator) first). Each image then appears centered within a separate slide.