More specifically, say there's a still photo of a valley with motionless rose petals in the air. How can I take those rose petals that are motionless and move each individual one in specific directions to make an animated image? At the moment, the missing pieces of the background that would show when moving the petals isn't a big issue.
The trick to extract your foreground elements, in your case rose petals, and then create/fill in the holes you've made. In AE that would mean using basically using the clone tool to use other parts of the photo to fill in the areas. If you use photoshop you can use a "content aware" fill, to accomplish this.
Here is a tutorial from video copilot that goes into detail on the entire process(though it's for creating a 2.5D image). Virtual 3D Photos
And here's a tutorial/overview on content aware fill:
Johnny Cuevas, Editor
"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.