Custom theme not working

I am using Ubuntu 18.04. Audacity 2.3.2 as Snap from Ubuntu Software. I have edited the ImageCache.png and put it in /home/myName/snap/audacity/489/.audacity-data/Theme. When I choose Edit>Preferences>Interface>Custom and then click " Ok " as mentioned in the Wiki, nothing happens. What is wrong. Can someone please guide me ? I am attaching the ImageCache.png image I modified.

The problem is probably because Snap packages run in a secure “sandbox” container, which limits their interaction with external resources. Whoever created the Snap package may be in a better position to help you.

Thanks Steve. I found the path at last