Delete photos from iPhone without iTunes
I have an iPhone 8 plus that has never been synced to a computer. I do not have iTunes and I don't have an internet connection currently, so downloading it is not an option. My iPhone is mad because it is almost out of storage and wants me to delete photos, but the delete icon is greyed out and it won't let me delete anything. Is there any way to fix this without a computer? My photos have all been backed up already.
iPhone 8 Plus, iOS 12