If we are to realise the vision of the authors of the WWW as quoted in the introduction applied to graphical information and to take up the challenge of Al Gore, we have to move beyond the lowest common denominator graphics we see as standard on the WWW. We need the standard versions of the browsers to have a wider range of formats accepted by their native form. We need to go beyond GIF to vector formats, 3D models and application-related data.
In realising this it is important to recognise the need for tools for informal and formal testing to help analyse any problems which may occur.
Indexing and metadata issues need to be addressed with regard to the more complex data types involved in graphical applications. The related topics of archiving and quality assurance are also issues.
Looking ahead it is possible that some of these problems may go away with the use of Java. The graphical data can come with appropriate software to handle the format. Maybe browsers will not be the issue, though the data types and file formats in use will still need to be broadened.
There are plenty of challenges!