FileMaker 13 introduces a couple new functions, Base64Decode and Base64Encode. Base64 is a commonly used method of encoding binary data as text. For example, it is a standard means of attaching files to email. When you attach a file to an email to send to a friend, your email application can encode the raw file as text using Base64. When the email is received, the program you use to read email decodes the attachment in order for you to save it to your computer.
This example file explores the new functions and shows how to begin using them.
Read more here: http://www.soliantconsulting.com/blog/2014/06/filemaker-13-working-base-64