I am running iOS 7 on an iPhone 4. I've noticed a really minuscule but annoying glitch/bug when I changed my lock screen wallpaper recently. This is my current lock screen wallpaper. As you can see it is almost completely black. When I swipe to reveal the Passcode screen, the circle outlines around the numbers as well the tiny circles at the top are not visible or barely visible (i.e. 5 because the white bits from my wallpaper bleed through). If I adjust the brightness in any way (less bright or brighter) from the lock screen as seen below... Then this happens... After locking my phone and then unlocking it it's back to how it was. At first I thought that this had something to do with the brightness settings but then why would it show the circles when I lowered the brightness? Made no sense. Then I turned off the contrast setting in Accessibility but that didn't change anything. Does anybody know a fix for this or is it just a really weird "bug"? Thanks!