I've got a client that launched their site a few weeks ago. Yesterday the client calls and claims that some of their IE6 viewers are unable to view the PNG files embedded into the page.
We QA'd on 7 PC's with IE6 installed and were not able to duplicate the issue as the PNG fix was working properly for us. We asked the client to come in and he did but as described the PNG files were not showing up for him on his browser using "IETester" to see it in IE 6 rendering.
I explained to him that it could be related to the fact that he is not using a true standalone version of IE6. Problem is - we downloaded IE Tester and had no problems with the PNG's.
I'm beginning to think that somehow the issue may be related to some OS or hardware problem. I made a simple png on background test page with the standard PNGFix and nothing else and we were unsuccessful getting the PNG to display for him.
It could be DirectX. I think PNGFix, and Internet Explorer as well, rely on DirectX to render the transparent parts of an image. Check the versions of DirectX against his, and if they're different, try upgrading his DirectX.
Start > Run > "dxdiag" > OK
The man who comes back through the Door in the Wall will never be quite the same as the man who went out.
To be frank, you should not use a render engine such as IPInfo's Netrenderer or a tool like IETester. The smartest thing to do, it simply download and/or install a WinXP installation. The best way to do this is to download a stripped Windows XP off the internet which isn't illigal, install this onto a downloaded, legal copy of Microsoft's Virtual PC 2007 (don't forget to install the SP1 update) and then check out the website. This, of course, only applies if you have Vista or XP with IE7 or higher. The standard, standalone version of WindowsXP (excl. SP1) provides you with the most noobish and utterly useless IE6.
Aside from this, there are numurous fixes that apply to transparency in IE6. I must've read over 20 articles on how to apply it, and yet I am not sure on which version to use. The TwinHelix version provides by xenon should do the trick just fine, but it's not the most perfect way. All and all, I like to avoid using transparency. If you do, make sure it doesn't have gradients. If not, you can simply use GIFs.
I keep praying for the day to come that everyone bans IE6 and all computers still using it just break down and explode. IE6 is a webdesigner's/webdeveloper's worse nightmare. Mozilla eat your heart out.