Add context menu to Thunar

This are the simple steps to add a context menu when clicking with the rigth button of the mouse in the selected file.

1. Go to edit -> Configure custom actions...
2. In the menu click on Add a new custom action.
3. Give it a Name that will be shown in the context menu
4. A Description
5. Write the Command to run (e.g. convert %F %F.png) where %F means the selected files
6. Go to the tab Appearance Conditions and choose the type of files that you want this context menu to appear (e.g. in the previous example we should choose Image Files)
7. Click OK and Close

I uploaded a video with all these steps in YouTube:

See a more detailed explanation here: http://pclosmag.com/html/issues/201008/page10.html