Add slow-zoom to PowerPoint images

Many documentary films are in fact a series of still images with a very slow zoom effect applied to them. The brain does not really notice that it is not looking at live video footage. The example below is my attempt to take you to the start of a story in the streets of Paris.

So how do you create these?
  1. Take an image and stretch it bigger than the PowerPoint canvas
  2. Select the object and pick an emphasis animation: either grow/shrink, or a motion path
  3. Set the effect option to very slow
In this case I used a "grow/shrink" with a 130% magnitude over 5 seconds.

Thank you Eole Wind for this beautiful image.