My Macbook appearance now has darkened images with a sharp contrast around the image edges. When I startup, the images look fine until the top menu bar appears at the end. At that point, all images in the dock have a sharper contrast and a darker appearance around the edges. The blue folder colors only appear in the bottom half of folders on the finder, the top half of the folder being white. Photos appear to darken and colors are distorted. I have tried changing everything possible in system preferences from the appearance, the display, and the desktop screensaver....nothing works. Anyone have a suggestion?