This is a fork of the Auto Save PSD script by joonaspaakko. It's modified to export PNG images of the document to the Desktop (or any other folder with minimal configuration). So, if you're working on Picture.psd, running this script will create Picture.png on the desktop.
Place the Export-PSD.jsx at {Photoshop_root}\Presets\Scripts\Export-PSD.jsx and restart Photoshop.
In the Export-PSD.jsx file, change the line that looks like
var desktop = '~/Desktop';
Change the ~/Desktop bit to whatever path you'd like.