I need to make more use of colour in the tables on the pages.
Thus I need to make the graphic images support alpha transparency.
Unfortunately most of my images were saved with a white
background, which means that I could not really change the
colour of a cell in a table (as it would leave a large area
of white around the graphic). If you want to see the effect
that it does, look at the two School of Computing logos
You can see that the one with the transparent background
takes on the background of the background colour, whereas
the other one has a fixed white background. This, is of
course, one of the great advantages of using GIF images
rather than JPEG, as you cannot add transparancy to a JPEG
So I'm just covering all my old graphics so that the white
background is covered into a transparent background. Once
PNG format is fully supported, it will be much easier to
define transparency, and also to use proper vector graphics.
Until then, we're stuck with GIF. Oh BTW it looks as if
there may be a licence fee charged for GIF compression in
the future, thus the sooner we use PNG the better.