Fade speed doesnt seem to do any effect

Hello,

On the plugins page: https://github.com/srobbin/jquery-backstretch#fade

This is the speed at which the image will fade in. Integers in milliseconds are accepted, as well as standard jQuery speed strings (slow, normal, fast). (type=Integer or String, default=0)

I am changing the value from the formatter's display options but it doesnt seem to change anything. I made it 5 and 5000, but the transition is always happened in the same amount of time.

One side note: It would be better if we include: "Integers in milliseconds" to the description of that setting.