What Hypertext is
A system for writing and displaying text that can be linked in multiple ways to related documents and available at several levels of detail. The term was coined by Ted Nelson to refer to a nonlinear system of information browsing and retrieval based on associative links between documents. The World Wide Web uses hypertext transfer protocol (HTTP) to link pages and multimedia files.
The meaning of Raster graphics
Also known as "bitmapped graphics" these programs store images in the form of patterns of screen pixels. Unlike "draw programs" (vector graphics), these "paint programs" can create detailed patterns of shading that convey an artistic touch, but any attempt to rescale or resize the image may result in unacceptable distortion. Raster-based graphics have become a standard technology and are popularly known by their GIF and JPG formats. Raster graphics use pixel-by-pixel definitions as opposed to vector graphics which use computer algorithms to describe shapes, lines, animation, etc.