An URL-field is created for CDS to show one image per record. The images for the URL are located on a SharePoint-List. So, the URL from SharePoint to a specific image is stored to the URL-field on CDS. These URL's to the images should be shown in Power Apps in a gallery control with the name and other information of the record.
It is possible to show the image from URL in Power Apps Studio. However, if we open Power Apps on mobile, the images are not shown. The image placeholder in the gallery remains empty for all records.
After some investigation, it seems that Power Apps on mobile cannot use URL's that requires authentication (e. g. SharePoint).
This feature is really needed, because we need to use our company images stored in SharePoint for our Power App.