Why is there something white behind the "slide to unlock" in my lock screen? (iPhone 4, iOS 7.1) I get the following lock screen on my iPhone:



The image was taken by myself, i added a filter from the iPhone Filters, and when I set this image as background, there is this white thing behind the slider. Why is it there and why is it only partially there? The original image looks normal, like this:
It's just the Slide to Unlock's shinning effect that is less subtle on an iPhone 4 with a black background.

Some of the iOS7 effects and animations, like Control Center's blurry background, are less fluid and subtle because of the processing power of the device.