I was frastruted by PNG files get from iPhone or iTouch. Apple changed format of the PNG files, most software in Mac or Windows cannot view them.

I searched this issue on web, found lots of people provide solution of it. Such as:

I am not familiar with Python, and more than 50% my time, I am working on windows, and I don't want to use a website to change PNG one by one. So I developed a Java application to do the same work by myselft.

Here you can find the executable Jar file and all Source code of it.

Hope it can help you.