FossifyGallery/app/src/main/AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest
    package="com.simplemobiletools.gallery"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name="com.simplemobiletools.gallery.activities.MainActivity"
            android:screenOrientation="portrait">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>

        <activity
            android:name="com.simplemobiletools.gallery.activities.PhotosActivity"
            android:screenOrientation="portrait"/>

        <activity
            android:name="com.simplemobiletools.gallery.activities.ViewPagerActivity"
            android:screenOrientation="portrait"/>
    </application>
</manifest>