Flutter update the app icon for IOS and Android

The default Flutter app created by the command line flutter create my_app has its own default icon for Android and IOS.

For Android: Those app icons are located at android\app\src\main\res within your flutter project.

For IOS: Those app icons are located at ios/Runner/Assets.xcassets/AppIcon.appiconset within your flutter project.

To Update the app icons, just replace the images found in those folder with yours. Here are some online app icon generator tools you can use to create app icons.
– https://romannurik.github.io/AndroidAssetStudio/index.html
– https://easyappicon.com/
– https://appicon.co/

The ios image app icons are configured in the Contents.json file within ios/Runner/Assets.xcassets/AppIcon.appiconset. No need to update this file, as long as the images are replaced with the the same image file names. The content in the Contents.json looks like this.

{
  "images" : [
    {
      "size" : "20x20",
      "idiom" : "iphone",
      "filename" : "Icon-App-20x20@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "20x20",
      "idiom" : "iphone",
      "filename" : "Icon-App-20x20@3x.png",
      "scale" : "3x"
    },
    {
      "size" : "29x29",
      "idiom" : "iphone",
      "filename" : "Icon-App-29x29@1x.png",
      "scale" : "1x"
    },
    {
      "size" : "29x29",
      "idiom" : "iphone",
      "filename" : "Icon-App-29x29@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "29x29",
      "idiom" : "iphone",
      "filename" : "Icon-App-29x29@3x.png",
      "scale" : "3x"
    },
    {
      "size" : "40x40",
      "idiom" : "iphone",
      "filename" : "Icon-App-40x40@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "40x40",
      "idiom" : "iphone",
      "filename" : "Icon-App-40x40@3x.png",
      "scale" : "3x"
    },
    {
      "size" : "60x60",
      "idiom" : "iphone",
      "filename" : "Icon-App-60x60@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "60x60",
      "idiom" : "iphone",
      "filename" : "Icon-App-60x60@3x.png",
      "scale" : "3x"
    },
    {
      "size" : "20x20",
      "idiom" : "ipad",
      "filename" : "Icon-App-20x20@1x.png",
      "scale" : "1x"
    },
    {
      "size" : "20x20",
      "idiom" : "ipad",
      "filename" : "Icon-App-20x20@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "29x29",
      "idiom" : "ipad",
      "filename" : "Icon-App-29x29@1x.png",
      "scale" : "1x"
    },
    {
      "size" : "29x29",
      "idiom" : "ipad",
      "filename" : "Icon-App-29x29@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "40x40",
      "idiom" : "ipad",
      "filename" : "Icon-App-40x40@1x.png",
      "scale" : "1x"
    },
    {
      "size" : "40x40",
      "idiom" : "ipad",
      "filename" : "Icon-App-40x40@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "76x76",
      "idiom" : "ipad",
      "filename" : "Icon-App-76x76@1x.png",
      "scale" : "1x"
    },
    {
      "size" : "76x76",
      "idiom" : "ipad",
      "filename" : "Icon-App-76x76@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "83.5x83.5",
      "idiom" : "ipad",
      "filename" : "Icon-App-83.5x83.5@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "1024x1024",
      "idiom" : "ios-marketing",
      "filename" : "Icon-App-1024x1024@1x.png",
      "scale" : "1x"
    }
  ],
  "info" : {
    "version" : 1,
    "author" : "xcode"
  }
}

The Android app icons are located at android\app\src\main\res with the following folders for different resolutions. Within each of these folders, there are usually 3 image icons. ic_launcher.png, ic_launcher_adaptive_back.png and ic_launcher_adaptive_fore.png