Exercise 3.4 -- Images and Graphics

In this week's exercise I edited images using the JPEG and GIF formats. The JPEG format is appropriate for displaying photographic images on the Web due to its relatively small file size, but data is lost when the file is modified and cannot be recovered. GIF files are lossless but larger in size than JPEGs and only support 256 colours (Matthews, 2004). They are more useful for graphs and greyscale images and, unlike JPEGs, can be transparent or animated. The PNG format is growing in popularity as it is lossless like a GIF but supports 16 million colours although the file size is larger than JPEGs and it is not supported by older browsers (ibid). Irrespective of the format chosen, it is vital to save an original copy of an image before editing it for use on the Web. The results of this week's exercise are available from: http://www.student.city.ac.uk/~abgy261/task4.html

Libraries are at the forefront of new techniques to digitally represent graphical information. MIT's SIMILE project spatialises digital information, creating maps and images which aid users navigating through information spaces. Mash-ups can be used to seamlessly combine data from several sources to create a new resource, for example integrating images from Flickr into OPACs (Engard, 2009) which can save time and deliver relevant information more quickly, ameliorating problems with information overload.

Digitisation is a socially and culturally important concern for libraries. Initiatives such as Google Book Search and the Open Content Alliance are trying to create a global library of information by converting books and historical documents into graphical formats, ensuring printed information is not lost forever. In addition to legal ramifications (Samuelson, 2009) there are also the practical limitations pertinent to all graphical information on the Web: the problem of maintaining quality and integrity while coping with limitations of user's bandwidth speeds.