Glossary

Accessibility

The characteristic of a web pages that defines how easily any visitor with a physical or mental disability can use the web page. Accessibility encompasses a number of factors such as how easily the page can be interpreted by a machine (such as a screen reader), how easily the visitor can change the presentation of the page to suit their needs and weather or not textual version of content are available anywhere an image, video or audio file has been used.

GIF

See Graphics Interchange Format

Graphics Interchange Format (GIF)

A widely supported file type used to store images and graphics. GIF files are widely used with in web pages as they tend to be small and so download quickly. GIF files also support transparency. GIF files don't offer very high quality representation of photos and are usually only used for graphics.

Joint Motion-Picture Expert Group (JPEG/JPG)

JPEG are a very common file format used to store photographic images. JPEGs are able to compressed the photographic data in a way that seems have offer very good quality. Although it does lose information and lowers the quality of the image, this isn't usually noticeable. JPEG files are very widely supported.

JPEG

See Joint Motion-Picture Experts Group

Multimedia

In computer terms, when we say 'Medium' we mean the basic type of technology being used to convey or interact with information. Medium could be text, HTML, Flash, Video, Audio. So, multimedia means to use technology that encompasses more than one medium at a time.

Portable Network Graphics (PNG)

A relatively new file format, PNGs are only just becoming widely supported. Internet Explorer 6 cannot always work correctly with this file type, although later versions do offer full support to display these files. PNG files have advanced features that allow them to store vector as well as raster data for an image. Vector PNGs are scalable, allowing them to be resized with out any effect on quality. PNGs also offer alpha channel transparency, meaning that they can blend semi-transparent colour regions of the image with background colours, to create a more seamless effect.

Usability

The measure of how simple and straight forward it is to use something, such as a web site. For example, making sure that filling in a form only needs to be done in a simple and obvious manner so that the user doesn't have to stop and think, let alone puzzle over how to use the web site.