One way would be to send an e-mail to Computer B with photo of Fido attached, and once the e-mail is received, print out the photo from that computer.  But after you send the e-mail and set off down the hall, you trip on an electrical cord and bang your head into the desk of Computer C (yeah that's right, Computer C).  This results in the smoldering cup of coffee sitting atop the desk to fall into the lap of your coworker - Bob.  Not only does Bob jump to his feet screaming like a schoolgirl, but you also melted a hole in his favorite polyester pants.  Then, an hour later after returning from the emergency room, you find that the e-mail is still sending because the file Fido.jpg is 100mb in size (really huge).  This doesn't include how long it'll take to receive the e-mail from Computer B.

Another way would be to network the computers.  Now you could share files, have access to Computer B's printer, and much more, all in the comfort of sitting at Computer A.  No more walking down the hallway.  No more sending e-mails with attached files from one computer to the other.  No more filling out long forms in the hospital emergency room. And once you experience the ease of your network, you will realize how unbelievably ridiculous it was the previous way (no offense).