Thinking of purchasing a pink third-generation iPod nano? If you’ve been wondering how the Valentine’s Day-ready iPod stacks up visually to its second-generation predecessor, we have some pictures you’ll want to see. Like the other third-generation iPod nanos, the new pink nano is less vibrantly colored than its predecessor, but by contrast with the radically dimmed blue, green, and red shades, the difference is small. This year’s…