Before you bemoan the retina display of the iPhone 4, take a look at these images from Ryan White and Bryan Gauntt, two PhD candidates from Penn State University. The pair compared the iPhone 4 and the 3G under a microscope and uncovered the stark difference in pixel size between the two displays. The iPhone 3G has pixels that measure 13 x 40 microns, while the iPhone 4 comes in with pixels that measure 6.5 x 20 microns. That means for every single iPhone 3G pixel, there are four pixels on the iPhone 4. Practically speaking, this higher pixel density will make images and text appear sharper on the iPhone 4 and is most revealing in the images the duo captured. Check them out after the jump and let us know what you think in the comments.