PNG8 Transparency Fireworks Trick – If we set our file format to PNG8 – indexed transparency, we get a result very much like any transparent GIF you might see. One color chip in our palette is set aside for the alpha channel, and all semi-transparent colors are flattened into the background color and rendered opaque.  However, if we switch from index to alpha transparency, things get interesting.

While our default alpha chip is still there, our PNG8 palette preview now shows a new type of color chip with a transparent chiplet cut out of the top-left corner. These are our semi-transparent colors.  This transparency works in all modern browsers IE7 included and degrades nicely in IE6 and below.  Without this trick you apparently get grey pixely bits around the image in earlier versions of IE.

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