PHP has a built in web server that was introduced in version 5.4.0. It is not suited for production but is great for easy development or quick testing. Here are a few ways to use it.
Two common libraries for image manipulation with PHP are GD and Imagick. GD typically comes with most PHP setups. Here are some code snippets that demonstrate how to crop an image with both libraries.
In Drupal 7 the theme and template layer can easily be over complicated, but this is the quickest and most effective way in my opinion to get started using template files in your custom modules. Get in the habit of using a template file instead of putting pieces of HTML inside your module code. This system is pretty flexible and you can create a template for a small item or for a whole page.
Arch Linux is my preferred Linux distribution. Not many of the VPS providers offer Arch Linux though. Here is my review of three options. It is worth mentioning that using Arch Linux for a critical server that needs to stay up is generally not recommended. Updates are frequent and they sometimes come with big changes. There are situations where the only way to fix something that breaks after an update is to read the news on the Arch Linux website. CentOS and Debian are good reliable choices.
Unit testing a TCP server and client can be tricky at first. Let me share what I've come up with for unit testing them. I will not provide full test class code just invidual test methods. If you don't know how to use unittest with Python and get your tests running refer to the unittest documentation. GameServer.Server and GameClient.Client are the classes that are being tested and which should be implemented elsewhere.
This covers how to install and start using mod_wsgi with Apache on Arch Linux.
Watch an interesting 30-minute marketing video/documentary about Unix from the AT&T Archives.