asset-management

Asset Management

Asset Catalog Structure

Xcode projects use .xcassets bundles containing named asset sets:

Assets.xcassets/
  Contents.json                    # Root catalog manifest
  AppIcon.appiconset/
    Contents.json                  # Icon set manifest with image references
    AppIcon.png                    # The actual icon file
  AccentColor.colorset/
    Contents.json                  # Color set manifest

App Icon Requirements by Platform

All platforms require a single high-resolution icon. Xcode generates all needed sizes automatically.

Platform	Size	Idiom	Platform Key
iOS	1024x1024	universal	ios
watchOS	1024x1024	universal	watchos
tvOS	1280x768	tv	tvos
macOS	1024x1024	mac	(none)
visionOS	1024x1024	universal	xros

Contents.json Format

iOS example:

{
  "images": [
    {
      "filename": "AppIcon.png",
      "idiom": "universal",
      "platform": "ios",
      "size": "1024x1024"
    }
  ],
  "info": {
    "version": 1,
    "author": "xcode"
  }
}

macOS uses "idiom": "mac" with "scale": "1x" and no "platform" key.

Image Processing with sips

macOS includes sips (scriptable image processing system) for image manipulation:

# Query dimensions
sips -g pixelWidth -g pixelHeight image.png

# Resize to exact dimensions
sips -z 1024 1024 image.png

# Convert format to PNG
sips --setProperty format png image.jpg --out image.png

# Resize and convert in one step
sips -z 1024 1024 --setProperty format png input.jpg --out output.png

Verifying Icon Installation

To verify an icon is correctly installed:

1. Check AppIcon.appiconset/Contents.json has a filename entry
2. Verify the referenced file exists in the same directory
3. Confirm dimensions match the platform requirement using sips -g pixelWidth -g pixelHeight
4. Build the project to verify Xcode accepts the icon

Finding the Asset Catalog