Why can't IE6 shows semi transparent png8 files with alpha filter ?

Question

-- read the whole question before answering --

Hi, i work on a big website that had a lot (45000+) of png24 images (with semi transparency).

I converted them to png8 and it works very well (a big help on page load time...).

The thing is i had to keep png24 files for ie6 users (with alpha filter to have semi transparent pixels) because we all know that we can't use png 8 semi transparent images in IE6 : either the semi transparent pixels will be opaque or completely transparent.

I tried to use the alpha image loader filter with png8 images but it just don't work, the pixels are still opaque/completely transparent, no semi transparency.

What's the reason it's not working ? Is there a difference for IE when dealing with semi transparent pixels from a png24 or from a png8 ?

I couldn't find any information on msdn websites or on stackoverflow...

This is crazy... !

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DISCLAIMER : i'm not searching for a f**ckin fix IE6 png or sh*t like that, i already know alpha image loader or htc techniques etc, theses all works well with PNG24 files but doesn't work with png8 files.

Answer 1

Because IE6 is old and crap.

It's been a while since I read this article but it may help (I can't remember): http://www.alistapart.com/articles/pngopacity/

G.

Answer 2

Because it sucks ... don't use transparent png's if you're targeting IE6 ... Blame microsoft ..

Answer 3

IE6 is garbage and time-killer for a web developer.

I think your question is not "why is it that bad" but rather "how can I fix it"?

Search google for "IE6 PNG fix", there are tons of scripts that will help you.

Answer 4

Even if you find a solution, the IE6 hack to handle semi transparency with PNG is extremely CPU consumming.

The better solution is to make your PNG8 "IE6-friendly" or you will kill your IE6 with only 5~10 PNG images

http://www.sitepoint.com/blogs/2008/03/20/making-ie6-friendly-png8-images/

Answer 5

In the end, the answer to the question "Why can’t IE6 show X" is simply "because IE6 does not have code to show X". Almost any feature, even those as small and trivial as this, require code to be written, reviewed and tested at least to the point where there are no horrible bugs left.

We can speculate how far PNG8 came. Did they even start coding, or did they encounter a tricky bug that crashed IE6 at times? That might be entertaining, but really not useful.

Answer 6

Use Supersleight. Great jQuery plugin!

http://allinthehead.com/retro/338/supersleight-jquery-plugin

I am a designer and sometimes you just cannot get away without using transparency and I HAVE to support IE6 still which is a pain, but this plugin has helped me a lot!