In Powerpoint, select the slide after which the images are to appear. You have just created a Powerpoint Slide Album. Then Export this Keynote file to Powerpoint ( File > Export To> Powerpoint.). Copy and paste the images you want in Powerpoint onto the Keynote Light Table. Add one slide and then switch to Light Table view.
However, you can make your own Slide Album in Keynote* by opening a new Keynote file with a white background scheme. One of the drawbacks of using Powerpoint on a Mac is that there is no Slide Album that will allow multiple images be inserted into the slide presentation the way you can in the PC version.
