AlphaPNG format plug-in by AlphaPlugins

Now you can save semi-transparent images with semi-transparent tones and an alpha-channel in 8-bit PNG format! AlphaPNG lets you choose your ideal color palette (RGB or Greyscale) and automatically optimizes it using our True-Color algorithm to convert your images into high quality indexed color PNG images with optimal dithering and optimized palettes.

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.