When you describe software (as an example) or generally what you or a device performs: First, a picture is shown on the

screen and then the program records the response of the user.. The topic is not the picture but your

focus is on the program which does this.

In the second sentence the focus is on the picture itself.

The picture shows on the screen and when there’s a mouse click, the

screen reopens. If you move the mouse click hides.