I’ve noticed today that I’m only getting the thumbnail included in the notifications when phone is connected to WiFi. If mobile-only, the notifications come sans thumbnail. It only drew my attention because I’m setting up a new phone, but looking into the old one it’s likely been doing this for some time.
Current setting is for “full effect”…would the behaviour be different if I changed to “Include Thumbnail”? My assumption is that notifications could take longer to come through if I do that, and I’d rather not encourage delays for the sake of a thumbnail being included.