Things we'll need:The prints folder filled with all the images
FastStone Photo Resizer (
http://www.faststone.org)
How to:-Download and install FastStone
-Open it
-Localizate your prints folder and open it
-Click "Add All"
-Configure Output settings (next point)
-Click Convert
Output settings:-Output format: PNG
-Output folder: Your icons folder
-Use advanced options:
+Resize tab:
*Tick Resize
*New width and height: 64
*The rest of the stuff leave it as it comes by default
This might be convenient for font packs, sign packs or stuff like that.