Clear the white and it doesn't blink.
Lets try this ONE more time.
When you save an image, all it saves is a flat image. If you made some stupid loving white layer to make the black seem to disappear, that gets flattened into it. AKA There's no longer an extra white bar, it's part of the background.
If you need more explanation, I'll loving kill you. I'm still having some stupid loving problem where it won't animate after I saved it.