From ICO to PNG
The above form produces .ICO files. This is fine, expect many image programs can't handle .ICO files. So here we convert them to PNGs that can be opened by almost all image editors.
PNG to ICO
You can also the the reverse of the above and pack multiple PNGs into one ICO file. Only the use of PNGs at this stage is supported. The maximum icon size is 256 which is imposed by the ICO file format itself, anything larger could result in a corrupt icon.