How does ppt make a white cloud from the distance slowly drifting through the animation?

How does ppt make a white cloud from the distance slowly drifting through the animation?

1, create a new PPT document, click "Insert--picture".

2, drag the picture, so that the white clouds cover the entire editing window.

3, click on the menu bar "animation-Custom Animation."

4, select the picture, and then click "Add Effect".

5, in the "Add Effect" select "emphasis--enlarge zoom out."

6, click the Action list items pop-up drop-down menu in the lower right corner, select "Timing" in the menu.

7, "Speed" select "Very slow", "repeat" select "until the next click."

8, by far and near the effect came out.

Note:

In the production before the best to trim the picture, the white clouds in the ground scene, the sky in addition to white clouds outside the sky of objects to cut, otherwise the white clouds move when these references also move, affecting the authenticity of the effect.