The cover photo is the image that appears on the workspace of your home screen:

The cover photo is also found at the very top left of your workspace.

Default cover photo

When the workspace is created, the cover photo is blank by default.

Changing the cover photo

In the workspace properties, in the workspace information section, add the photo you want to customize your workspace tool. 

Choose a cover photo

Click on Edit pictore and then select the image you want from your computer's browser.

The image becomes the workspace cover photo.