info.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTDPLIST1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
    <dict>
        <!-- ...the rest of info.plist -->
        <key>CFBundleIcons</key>
        <dict>
            <!-- Default app icon -->
            <key>CFBundlePrimaryIcon</key>
            <dict>
                <key>CFBundleIconFiles</key>
                <array>
                    <string>black</string>
                </array>
                <key>UIPrerenderedIcon</key>
                <false/>
            </dict>

            <key>CFBundleAlternateIcons</key>
            <dict>
                <!-- First custom icon - Black -->
                <key>black</key>
                <dict>
                    <key>CFBundleIconFiles</key>
                    <array>
                        <string>black</string>
                    </array>
                    <key>UIPrerenderedIcon</key>
                    <false/>
                </dict>

                <!-- Second custom icon - Gradient -->
                <key>gradient</key>
                <dict>
                    <key>CFBundleIconFiles</key>
                    <array>
                        <string>gradient</string>
                    </array>
                    <key>UIPrerenderedIcon</key>
                    <false/>
                </dict>

                <!-- Third custom icon - Galaxy -->
                <key>galaxy</key>
                <dict>
                    <key>CFBundleIconFiles</key>
                    <array>
                        <string>galaxy</string>
                    </array>
                    <key>UIPrerenderedIcon</key>
                    <false/>
                </dict>
            </dict>
        </dict>
        <!-- ...the rest of info.plist -->
    </dict>
</plist>