This picture service is a Micro-Web-Framework Challenge done as part of an assessment for their candidates.
I chose Sinatra as the framework of choice out of the options given as I have been pretty fascinated by Ruby for some time already, so I gave it a shot.

You will need to install the following gems:

gem install sinatra
gem install puma # or any other server
gem install rack-test
gem install rubyzip

Once the gems are all installed, you may run the service with:

ruby service.rb

If you would like to run the test file, you may run it with:

ruby test/service-test.rb