require 'open-uri'
open('http://pragprog.com') do |f|
  puts f.read.scan(/<img alt=".*?" src="(.*?)"/m).uniq[0,3]
end

C:/RailsInstaller/Ruby2.0.0/lib/ruby/2.0.0/open-uri.rb:223:in
`open_loop': redirection forbidden: http://pragprog.com ->
https://pragprog.com/ (Runti meError)
        from C:/RailsInstaller/Ruby2.0.0/lib/ruby/2.0.0/open-uri.rb:149:in
`open_uri'
        from C:/RailsInstaller/Ruby2.0.0/lib/ruby/2.0.0/open-uri.rb:688:in `open'
        from C:/RailsInstaller/Ruby2.0.0/lib/ruby/2.0.0/open-uri.rb:34:in `open'
        from ./lib/methods.rb:123:in `<main>'

require 'open-uri'
open('http**s**://pragprog.com') do |f|
  puts f.read.scan(/<img alt=".*?" src="(.*?)"/m).uniq[0,3]
end