I followed the picture, but I met a problem.
In eclipse I have my packages like mods.roserod.textures.items
I must put my png files in a path like E:\Minecraft152\.minecraft\mods\roserod\mods\roserod\textures\items
It works.
@Override
public void registerIcons(IconRegister iconRegister) {
itemIcon = iconRegister.registerIcon("roserod:roseRod");
}