Open Photoshop and open the desired image to be animated.
Create a blank layer above the image layer.

File > Jump To > Image Ready 3.0
Make 4 copies of the image layer. Select the bottom layer.
Edit > Transform > Numeric
In the box, input 20 % under scale - Percentage.
The image will get contracted.
Repeat the procedure for above three layer using 40%, 60%, 80%.

Make Frames from Layers.

In the animation palette select 5th frame and tween it with the blank frame.
Set the timings for frames.
Set the no. of time you want to play the animation.
Check the performance in the browser.
File > Preview In > Click the browser you want.

Save the file with File > Save Optimized or File > Save Optimized As