Address some review comments

docs/maintainers.md

@@ -126,7 +126,6 @@ The following people (used to) maintain DevDocs:
 - [Jed Fox](https://github.com/j-f1)
 - [Mrugesh Mohapatra](https://github.com/raisedadead)
 - [Oliver Eyton-Williams](https://github.com/ojeytonwilliams)
-- [Paul Sernatinger](https://github.com/oscillot)
 - [Simon Legner](https://github.com/simon04)
 - [Thibaut Courouble](https://github.com/thibaut)
 

lib/docs/filters/core/images.rb

@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require 'base64'
 require 'image_optim'
 
 module Docs