Game icons: The inkatlas file
Apart has prepared a reference project with an import-ready inkatlas. You can download it here.
Summary
The .inkatlas is a map file that slices textures into slots, which are then used by the game for pretty much everything that is a picture - from your HUD to peoples' phone avatars to item preview icons in shops or custom atelier images.
Guides
For a guide how to create custom icon previews, see here.
For a guide how to create a custom Atelier icon, see here.
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