How to install and use.
Download the AlphaPNG installer and launch.
The installer will automatically locate your "Photoshop Plug-ins > File Formats" folder and install the plug-in here.
Launch Photoshop and open any image.
In the file menu, click "File > Save As"
Select the file type "AlphaPNG" and enter the new PNG file name and click "Save" to launch the AlphaPNG plug-in.
Adjust the parameters of the PNG as you desire and click "Save". As you work with the plug-in, immediately see the results in real-time including the size of new PNG file in status bar. The preview window is scaleable and can be dragged to change its size.