Running a Tkinter form in a separate thread

Tkinter isn't thread safe, and the general consensus is that Tkinter doesn't work in a non-main thread. If you rewrite your code so that Tkinter runs in the main thread, you can have your workers run in other threads.

The main caveat is that the workers cannot interact with the Tkinter widgets. They will have to write data to a queue, and your main GUI thread will have to poll that queue.

If all you're doing is showing images, you probably don't need threading at all. Threading is only useful when you have a long running process that would otherwise block the GUI. Tkinter can easily handle hundreds of images and windows without breaking a sweat.

From your comments it sound's like you do not need a GUI at all. Just write the image to disk and call an external viewer.

On most systems it should be possible to launch the default viewer using something like this:

import subprocess subprocess.Popen("yourimage.png")

From what I can tell, Tkinter doesn't like playing in other threads. See this post...I Need a little help with Python, Tkinter and threading

The work around is to create a (possibly hidden) toplevel in your main thread, spawn a separate thread to open images, etc - and use a shared queue to send messages back to the Tk thread.

Are you required to use Tkinter for your project? I like Tkinter. It's "quick and dirty." - but there are (many) cases where other GUI kits are the way to go.