Graphic design is the process of communicating visually using text and images to present information. Graphic design practice embraces a range of cognitive skills, aesthetics and crafts, including typography, visual arts and page layout. Like other forms of design, graphic design often refers to both the process (designing) by which the communication is created and the products (designs) which are generated.
Web
Graphic designers are often involved in web design. Combining visual
communication skills with the interactive communication skills of user
interaction and online branding, graphic designers often work with web
developers to create both the look and feel of a web site and enhance the online
experience of web site visitors.
In the job field, many companies look for someone who can do both graphic design
and the web application development involved in web design, including
programming. There is a great deal of debate in the professional design
community about whether this trend is positive, or if graphic designers are
being over-tasked with unrelated skills and disciplines. A collaborative
web-design team may split the tasks between graphic designers and software
engineers.
From: http://www.wikipedia.org