I'm not sure you can change the taskbar image to different from the exe icon. what is the purpose to have different image on the taskbar? I don't think I have seen an software that has different taskbar image. Note we are talking about the taskbar, not the tray
ADDITION: What you have shown as icon is the tkinter icon.So you didn't change the exe icon either?
ADDITION: What you have shown as icon is the tkinter icon.So you didn't change the exe icon either?