Photoimage on button appears pixelated when button is disabled

[Dustan]

In tkinter, when I place a photoimage on a button and disable the
button, the image has background dots scattered through the image.
Searching the web, I wasn't able to find any documentation on this
behavior, nor how to turn it off. So here I am. How do I keep this
from happening?

Also, how can I extract the base-64 encoding of a GIF, so I can put
the image directly into the code instead of having to keep a separate
file for the image?

All responses appreciated,
Dustan