Ion-scroll for big image

Ionic Framework ionic-v3
1

I have a big image and want an effect as in docs for ion-scroll

there is the code

<ion-scroll scrollX="true" scrollY="true" zoom="true">

       <ion-img src="assets/img/maps/overview-1.png"/>
  </ion-scroll>

css:
ion-scroll { white-space: nowrap; }

It’s very wide image
but X scroll doesn’t work and image is very narrow

Whas’t wrong?