Common browsers are netscape, microsoft's internet explorer, and mosaic, to name only three. There are many others, and there are many versions of each one.
Browsers are avaialable for PCs, macs, and unix machines.
The browser software not only takes care of your graphical interface, but also handles connecting with other networked computers to bring you webpages from anywhere in the world. A graphic can be hotlinked also, in two ways.