My workflow re grey placeholders:
1. In GSAK: Database/Grab Images2. In GSAK: File / Export / GPX3. File Test1.gpx moved to Dropbox4. In Cachly: Import GPX, Import from Dropbox, Options Save Images, Import5. Printscreen of map with cache6. cache opened, Images - 5 visible7. back to map, three dots, Update caches, Visible, Full Cache Data8. Four pictures still visible, instead of fifth image is placeholder and added other placeholders (btw Mobile Data are On in the iPhone and LTE coverage is great)Mostly I do have after this process place holders instead of ALL images.
Images uploaded, gpx file is not supported, so look at the e-mail.