We will be finishing off our chat application by using threads to get it listening for incoming messages in the background. We will explore the motivation for incorporating threads in a GUI application, then learn how they can be implemented.

Once our application is listening for new messages, we will polish things off by making the user-chosen avatars function properly and we will learn how to handle manipulating images in Python.

We'll finish up by allowing users to add each other as friends and block friends if they no longer wish to talk to them.

In this chapter, we will cover the following topics:

• Why we may need to use threads when making a GUI application
• How to create and use a thread in Python
• Manipulating images using Python Imaging Library (PIL)
• Uploading images to a web service