Media Section crops images differently for different devices. For example, the image is cropped differently on iPad and an iPhone. It seems that the image gets cropped based on the screen size.

1. Navigate to sys_sg_media_section and create a new record.
2. Select the type as image and upload an image
3. Submit the record.
4. Now navigate to System Mobile -> Applet launchers
5. Open the Applet launcher "Homepage"
6. In the Applet launcher section of the record, Add the media section
7. Save the record
8. Open Now mobile app on an iPad and an iPhone

The image is cropped differently based on device display size.

This is expected behaviour in all currently supported releases, the image content mode by design is scale aspect fill.