title: Get Image File Size From Base64 String
body: <p>I'm working on a python web service.
  It calls another web service to change the picture of a profile.</p>
  
  <p>It connects to another web service.
  This web service can only accept pictures that are 4 MB or smaller.</p>
  
  <p>I will put the checking in the first web service.
  It uses PIL to check if the base64 string is a valid image.
  However, how do I check if the base64 string will create a 4 MB or smaller image?</p>