Why not use Moi itself ?... 
At the end use the Print Screen Key and past in any 2D prog for have your image to manage ! :)
 
In the free Fotosketcher for example! (by a talentuous French guy) ;)
 https://fotosketcher.com 
(you can resize your image in 64 * 64 pixels if you want...and some other cool things! 
here the process (all take 10 seconds! ;)
 
Past your save Screen from the ClipBoard 
Crop / reframe 
Permute image  
Apply an effect if necessary 
Resize image 64*64 
Save you image 64*64 
et voila :)
 
here just for validate the process
  
 
Here the image.jpg from fotosketcher  
you can now apply your Base 64 beautity...
  
so the icon will be maybe something like that or smaller/bigger following the Options/ UI size of Moi...
   
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