PNG Optimization Guide: More Clever Techniques

This post is a second part of the article Clever PNG Optimization Techniquesthat we posted last week. As a web designer you might be already familiar with the PNG image format which offers a full-featured transparency. It’s a lossless, robust, very good replacement of the elder GIF image format. As a Photoshop (or any other image editor) user you might think that there is not that many options for PNG optimization, especially for truecolor PNG’s (PNG-24 in Photoshop), which doesn’t have any. Some of you may even think that this format is “unoptimizable”. Well, in this post we’ll try to debunk this myth.

This post describes some techniques that may help you optimize your PNG-images. These techniques are derived from laborious hours spent on studying how exactly the PNG encoder saves data. We'll talk about grayscale, how to use fewer colors for optimization and also about reducing detail to minmize the file size.

refer to :http://www.smashingmagazine.com/2009/07/25/png-optimization-guide-more-clever-techniques/