In the p2p printing image below a workstation has a printer connected to it that's shared on the network, which allows the other network hosts to send print jobs to it.
In the p2p storage image, a workstation has a huge hard disk drive installed. Since the workstation is networked to other workstations, they are allowed to share the extra hard disk space. If a user needed to save, they could save it over the network connection to this system's extra hard disk space.
As you can see in these situations, the network hosts both provide and consume network services at the same time. These two hosts provide a network service. One provides printing, and this one provides extra storage. At the same time, all these hosts consume services and function as both a client and a server at the same time.