In a transparent GIF, one of the colours making up the GIF
is designated to be transparent. Wherever this colour is the background
colour/pattern of the Web page will show through.
When choosing a background colour make sure that the colour
does not appear in the image elsewhere, as these areas also become transparent.
With photographs it is often necessary to use a image program,
such as photoshop, to convert the areas of the picture you want to be transparent
and set them to one colour. You should do is with the image before converting
it to a GIF as the quality of the image will be better, i.e. you only need
one colour for the background rather than a number of colours to represent
the background.
A good choice for the transparent colour is a light gray such as #C0C0C0.
Since if the viewer does not support transparent colour, this is close to
the standard backgrounds.
Original On A White Background
Backgound Colour Set As Transparent
Background Changed To Blue,
A Colour Not In The Image
