Note that in all three cases above the display size is “only 10 pixels smaller” than the natural size of the image. However, the number of extra pixels that we would have to encode and ship is significantly higher the larger the natural size! As a result, while you may not be able to guarantee that every single asset is delivered at the exact display size, you should ensure that the number of unnecessary pixels is minimal, and that your large assets in particular are delivered as close as possible to their display size.