YSlow: Avoid AlphaImageLoader filter More Recommendations

Rule Summary

CSS
Medium
Moderate
96%

Overview

IE's AlphaImageLoader blocks rendering and increases page load times.

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Details from Yahoo!

The IE-proprietary AlphaImageLoader filter attempts to fix a problem with semi-transparent true color PNG files in IE versions less than Version 7. However, this filter blocks rendering and freezes the browser while the image is being downloaded.

Additionally, it increases memory consumption. The problem is further multiplied because it is applied per element, not per image.

recommends:

The best approach is to avoid AlphaImageLoader completely and use gracefully degrading PNG8 instead, which are fine in IE. If you absolutely need AlphaImageLoader, use the underscore hack _filter as to not penalize your IE7+ users.

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