My photos turned into blue negatives
After opening photo library on newly-acquired iphone SE 3rd gen, all my photos turned into blue negative looking images.
I found comments the Community discussion (some very old) commenting on similar problems, and also through web searches. It seems that the Smart Invert feature meant to enhance desktop appearance can sometimes affect photos, although it's not supposed to. The fix for me was to go to Settings > Accessibility > (scroll to bottom) > Per App > Add app, add Photos > (scroll down to) Smart Invert, turn off.
I did the same for Safari, as photos in the browser were also blue.
iPhone SE, iOS 18