iCloud photos
I am running IOS12 and High Sierra 10.13.6 on my iMac. I have iCloud Photos enabled on my iMac. I would like to enable iCloud storage on my iPhone so that the photos are available everywhere, but do not want them removed from my phone. I am not doing this to save the storage space on my phone, just for convenience, so the the photos are available.
On the Mac there is the option to keep the originals on the Mac, but I do not see any such option on the iPhone. What happens when I am not connected to WiFi, photos that I want to show are now sucking up data usage? Or worse yet, what if I am in a no service area. Would I then have NO photo's, or would I have low quality images in their place?