Graphic Designing - creating the visual arts / images / illustrations, etc.
Web Designing - creating the web pages. The web page has images, arts, illustration, logo, pages, layout etc ... all the things like logo, page layout, image are created by Graphic Designer
The front end designing of a web page is web design. A web designer provides an overall look and feel to the website. But the elements like logo, images in a web page are created by a graphic designer. A web designer has lots of restriction. They have to make an entire structure of the website. So they need to concentrate on page loading speed, resolution etc.
Graphics relates to all visual content and designing it is called Graphics Design, where as Web design is specially focused on designing the appearance of websites.
Both professions use different skills, with Graphic Design focusing more on artistic skills, and Web Design having an emphasis on programming and knowledge of the web, although there is quite a bit of overlap in both fields.