Adding @2x and @3x pictures without 1x version

Question

I've started developing an iOS app, adding pictures in resolution which is ok for standard retina screens. Now I want to add @3x pictures for iphone 6 plus and 7 plus. I don't want to include 1x version for older devices. I've renamed all image files to name@2x but these are not recognized in the project anymore. I was thinking that @2x name modifier will be ignored, but this is not the case. Do I need to explicitely add "@2x" in all places I'm referencing these pictures in the code? Or should I leave standard retina versions without any name change and these will be used anyway as @2x and only use @3x name modifier for higher resolution versions?

Answer 1

Use asset catalogs. See Apple Documentation

Then it's really easy to define 1x, 2x and 3x images by drag&drop. If you load the image in code by name (without scale) it works like a charm. If 1x is missing the next possible image will be used automatically.

Answer 2

您可以将pdf图像或众所周知的矢量图像作为单个矢量导入资产中 。因此，无需分别使用1x,2x,3x 。

Answer 3

You can use Blade

Better asset workflow for iOS developers. Generate Xcode image catalogs for iOS / OSX app icons, universal images, and more.

with a definition file like this will generate all the images for you and put it in the right place

blades:
- source: store/slice1.png # this image should be the only image, and the biggest image you can use (typically for icons, 1024x1024)
  mount: Project/Assets.xcassets/AppIcon.appiconset