The three adjacent images highlight the benefit of
PNG over GIF, as shown in a web browser. The first
illustration shows two PNGs on a white background.
The second illustration shows this background replaced
by a grid. Note how the button??™s drop shadow is partially
see-through, while the circle??™s center is revealed
as being partially transparent, increasing in opacity
toward its edge. The third illustration shows the closest
equivalent when using GIFs??”the drop shadow is
surrounded by an ugly cutout, and the circle??™s central
area loses its transparency. Upon closer inspection,
the circle is also surrounded by a jagged edge, and the
colors are far less smooth than those of the PNG.
Other image formats
You may have worked on pages in the past and added the odd BMP or TIFF file, or seen
another site do the same. These are not standard formats for the Web, though, and while
they may work fine in some cases, they require additional software in order to render in
some browsers (in many cases, they won??™t render at all, or they??™ll render inconsistently
across browsers). Furthermore, JPEG, GIF, and PNG are well-suited to web design because
For more information about this format,
check out the PNG website at www.libpng.
org/pub/png.
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they enable you to present a lot of visual information in a fairly small file. Presenting the
same in a TIFF or BMP won??™t massively increase the image??™s quality (when taking into
account the low resolution of the Web), but it will almost certainly increase download
times.
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