Ruby code:

#!/usr/bin/env ruby

(0..10).each do |row|
  (0..14).each do |col|
    `wget [url]http://www.ford.com/global/2015mustang/img/gallery/music-man/tiles/TileGroup0/4-#[/url]{col}-#{row}.jpg`
  end

  tile_jpegs = (0..14).map do |col|
    "4-#{col}-#{row}.jpg"
  end

  `convert #{tile_jpegs.join ' '} +append 4-#{row}.jpg`
end

row_jpegs = (0..10).map do |row|
  "4-#{row}.jpg"
end

`convert #{row_jpegs.join ' '} -append musicman.jpg`