Just recently, there have been some slight changes to the the way the skins section is organised. The [HD] tag in front of skins in the resources section (
example) means that the texture is in 512x512 resolution (as opposed to the standard 256x256).
Keep in mind that including a 256x256 version of the texture is still mandatory for approval, just now it's easier to tell the high-res/cinematic skins from the standard ones.