In order to adjust the desired picture section go to "Files" and click the blue box with 3 white dots next to the file used. As soon as you click on "Adjust image detail...", a window opens, in which the desired image section can be selected using the horizontal and vertical sliders.

Please keep in mind:

Due to Pageflow's responsive approach and the aim to always show images in full panel (without black bars top/bottom or left/right) background images and background videos are zoomed in. 

Motifs/graphics should therefore always be positioned or selected within a "safe area" in such a way that they also work in portrait mode (9:16 within a 16:9 background).

For consecutive pages with the same background image, the image details must be set identically to enable seamless scrolling.