Web Images: Introduction
The involvement of computers in imaging can be dated back to 1965, with Ivan Sutherland's Sketchpad project, which demonstrated the feasibility of computerized creation, manipulation and storage of images (Eakins, 1998).
The pre-Mosaic Web was homogenous in design. Typical pages consisted of pure black text rendered in the browser's default font setting, set against a white or grey background. The only features that stood out were coloured hypertext links and headings that were marked up using standard HTML header tags. It wasn't until the advent of GUI interfaces that the Web achieved mass appeal. If Mosaic proved anything, it is that people like graphics.
Today's corporate websites rely heavily on the use of images to promote brand recognition and raise their prestige. Usability expert, Norman, recognized the "connection between usability and aesthetics" which until recently were considered "two distinct spheres". He stressed, "usability alone does not suffice; websites and products should also be fun, enjoyable. This means aesthetically pleasing and exciting, depending upon the image one wishes to convey. There is no such thing as a single rule for all purposes" (Norman, 2002b).
Computer graphics generally fall into two distinct categories: vector and bitmap. Common imaging tools used to create bitmap files include Adobe Photoshop and Jasc's Paint Shop Pro. Popular bitmap formats include PSD, PICT, BMP and TIFF.
However, none of these formats are used on the Web because their file sizes are much too large to download in the time required for good usability. The rule of thumb is: "If you don't have fast images, you won't have fast pages" (Veen, J. 1997). Tweaking HTML code, incorporating style sheets and shortening sentences all have negligible effects on file size when compared to the file size of images. "Because file size is important in electronic publishing, file compression is an absolute must." (Adobe). Compression does not decrease resolution; it simply makes the file smaller.