This is something that irritates me about high dpi displays. If you have a small 16x16 icon and go to high dpi, often a regular 32x32 icon is used. So you just use a larger low dpi icon. The problem is that the icon at the same physical size now has much more details and looks less clear. The correct thing to do would be to have a separate 16x16@2x icon with 32x32 pixels, that is intended for the same physical size as the original 16x16 icon.