Thread:Lunarity/@comment-4190137-20130122054659/@comment-5209426-20130122070839

I looked at how it works. The images are a  pseudo-element, you can find it in Lightbox.scss. The reason it's black is because those buttons are using the secondary button palette. The button secondary palette is the page color (white) blended with the opposite color (black), i.e. grey-white.

If you remove the water wallpaper then you can see the image color lines up with that. Changing that is a problem since manually altering the sprite is fragile. You can reconfigure theme designer to make the page black instead of white but that will also change the text color to white as well as affecting the background color of previews, the lightbox and and a heap of other knock-on effects against page borders and such.