Very quick ruby script to create a bash script that will create a montage of your org.

create-org-montage.sh

# Set OCTOKIT_ACCESS_TOKEN to authenticate with a PAT
# Something like OCTOKIT_ACCESS_TOKEN=<<TOKEN>> bundle exec ruby create-org-montage-script.rb

require "octokit"

Octokit.auto_paginate = true

# Replace <<ORG_NAME>> with your GitHub org
members = Octokit.org_members "<<ORG_NAME>>"

open('org-montage.sh', 'w') { |f|
  # Yeah, I'm creating a bash script in Ruby - bite me
  f << "#!/bin/bash\n"

  members.each do |m|
    f << "curl " + m[:avatar_url] + " --output images/" + m[:id].to_s + ".jpg\n"
  end

  # Uses 'montage' command from ImageMagick (apt install imagemagick)
  # http://www.imagemagick.org/Usage/montage/
  # You probably want to play with the number across here to get a 16:9 image.
  # I'm creating an image that is 58 images wide made up of 48x48 pixel tiles.
  f << "montage images/*.jpg -resize 48x48 -mode Concatenate -tile 58x ghmontage.jpg\n"
  
}

For posterity, this work has been incorporated into https://github.com/andyfeller/gh-montage as an easy to use GitHub CLI extension!