+1  A: 

Please define "poor quality". Maybe it's because your CSS sprite didn't preserve the original image's transparency?

Wim Leers
please see thiscupacupelor dot ro/img/problem.pngpoor quality means IE re-encode the image in a poor format
pixel3cs
I have to concur; it's because of IE's inadequate support of transparent .png images. (unless it's not really an image and I'm misunderstanding. What's the URL of the affectd page?)
David Thomas
+3  A: 

Do you need to have the graphic in PNG format? Traditionally, Internet Explorer 6.0 and earlier had some issues relating to the PNG format, most notably the lack of support for the alpha channel.

Without this alpha channel, IE can't render the transparency represented in PNG images correctly. This might distort the image a bit, or give you something other than what you were expecting to see.

Without more details it's hard to discern what's causing the problem (or what the problem is in the first place).

Jacob Hume
It's a PNG image but with no transparency in itI have IE7 installedOk, i'll try to make the image JPG and i'll post back, I use PNG because they look better than JPG images
pixel3cs
+1 png in IE6 is horrific. Use gif or jpg only in IE6.
Geoff
A: 

Strange behavior, not expected.

Even if I have IE 7 and PNG with no transparency, backgrounds rendered with background-position style work weird in IE.

Saving the image as JPG and modify the CSS solved the problem.

Than you guys, I voted the answers.

pixel3cs
you can edit your post
Malfist
And accept an answer, returning the favour is always good.
David Thomas