In the old days, webmail was primarily used for sending and receiving email. In fact, most of the available webmail services in earlier times didn't even allow attachments, be it photos or any other documents. Fast forward to now. Google allows around 1GB of email storage and keeps on increasing each day. Yahoo! Mail lets you keep as many of your emails for as long as you want with unlimited storage. Microsoft Live Mail allows 5GB of storage. And there are other webmail platforms, too, each of them offering various storage capacities.
With these large storage capacities and few limits on the number of files that you can attach to your email, webmail can be used as an online storage and back up facility which should give you a good amount of storage capacity. Here are a few tips for using webmail in this manner.