Programmatically detect dark mode in SwiftUI to display appropriate Image

How to detect dark mode

struct ContentView: View {
    @Environment(\.colorScheme) var colorScheme

    var body: some View {
        Text(colorScheme == .dark ? "In dark mode" : "In light mode")
    }
}

Source: https://www.hackingwithswift.com/quick-start/swiftui/how-to-detect-dark-mode

There's an @Environment variable.

@Environment (\.colorScheme) var colorScheme:ColorScheme

Here's how I use it to fill an empty Rectangle:

Rectangle().fill(Color.fillColor(for: colorScheme))

You can use @Environment(\.colorScheme) var colorScheme: ColorScheme in any view to get whether the device is in dark mode (.dark) or light mode (.light). Using that information, you can conditionally decide which image to show easily with a ternary operator.

For example, if you have an image named "lightImage" for light mode and "darkImage" for dark mode:

@Environment(\.colorScheme) var colorScheme: ColorScheme

var body: some View {
    Button(action: {
        foo()
    }) {
        Image(colorScheme == .light ? "lightImage" : "darkImage")
    }
}