[sialivi]

AFAIK there is no way to control how long each fanart backdrop image will be shown from the settings screen.

If there's too much work to add this to the settings screen, perhaps the backdrops could use the same duration and transition time set under Pictures / Slideshow?

[djh_]

There's no way of making this user-definable, I'm afraid. Nor are there any plans to change the timings.