Having trouble reading your icon text over that snazzy background picture? Just change the background color for that Workspace so it’s similar to the dominant color of the bitmap, and the icon text color will change automatically. Icon text color changes dynamically between black and white depending on the background color, but it can’t determine the dominant color of a background bitmap automatically.
For instance, if you have a very dark picture, just change your background to be black. You might want to turn off icon label backgrounds as well. This will make your icon text color white, which is nicely offset against the dark picture.