Bad satellite imagery
Marble's preloaded NASA satellite imagery is not high quality and cannot be used to look at any precise details. Sentinel images allow you to get closer, but are still not detailed and do not seem to work for most of the world. I went to Marble's website to review documentation on adding new maps, and found it to be next to nonexistent. I found this page https://marble.kde.org/maps-4.5.php and tried to download the MapQuest satellite images in hopes of better quality, but all download links result in 404 errors. There are no instructions on how to utilize satellite images from another source besides those you provide. How can usable satellite data be loaded?