Optimize Images For Your Website - Png Crush Tutorial
http://letsbuildwebsites.com/optimizi... there are many ways to optimize images before uploading to your WordPress website but this one is very easy and does not involve installing a plugin. I think the less plugins the better.
You can crush smush reduce your png image before uploading to Wordpress.
The awesome Smushit wordpress plugin started to cause problems for me so I had to look for an alternative.
Pngcrush is an open source program and you can see more info at this link http://pmt.sourceforge.net/pngcrush/