NiFi - Using Groovy to convert image to byte array

[#1]

I need to convert an image to a byte array using nifi. I believe groovy is the only way to do this using nifi. Any ideas how to convert image to byte array? or if there is another method to do this in nifi? thanks

[#2]

You can find the answer with this link

http://mrhaki.blogspot.kr/2009/11/groovy-goodness-base64-encoding.html