Conversion of png files to icns file format

PNGs much like other images like JPG can be used to create icons, or form whole icon packs like the ICNS format for Apple Mac OS X. Your best shot would be to use some of the dedicated icon editing and making software like IconWorkshop.

Open PNG file    Open ICNS file

Related software

Image2icon icon

Image2icon

Create your own mac icons

Preview icon

Preview

A basic document and image viewer in Mac