These are the sizes that the documentation recommends for custom icons now.
- @2: 50 x 50
- @3: 75 x 75
Create two images of the above pixel sizes and then add them to a new image set in your Assets.xcassets file. (Apparently the @1 size is no longer needed.)
Alternatively, you could use a universal vector image (pdf) (see here and here). This has been my preference recently.
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