It often makes sense to display a portrait-format image for smartphones and a landscape-format image for all other devices. This is how you proceed:

1. Place a Picture element on your page and select a portrait-format image
2. In the Right Toolbar, under the Visibility tab, you will wee options for different devices
3. Only select the option Show on phone
4. The image has now disappeared from your preview area in the Website Builder. This is because you are currently displaying the page on your desktop computer.
5. In the page structure you will still see the image - grayed out and in italics. You can select the image here to make changes.
6. Next, drag an image element onto your page and select a landscape-format image
7. In the Right Toolbar, under the Visibility tab, select the options Show on wide screen, Show on desktop and Show on tablet
8. You have now defined a portrait-format image for mobile devices and a landscape-format image for all other device classes.