I have a Kirby 4.x site running on Apache using the default gd thumbs driver (with gd being enabled, confirmed using phpinfo). None of my thumbnails are generated, although the media directory is created. I see .jobs directories under media/pages//. Any pointers on how to debug this?
Which Kirby version? Which environment (local dev or remote server), if local, what setup? Which driver (no config setting = default gd), installed plugins if any, problem reproducible with a fresh Starterkit etc…