diff --git a/.gitignore b/.gitignore
index d879603d..1d76c5b1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,5 +14,6 @@
 .cxx
 .idea
 app/release
+app/debug
 app/lint
 lint
diff --git a/app/build.gradle b/app/build.gradle
index 705a0e0a..e045470c 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -36,6 +36,7 @@ android {
     sourceSets {
         main.java.srcDirs += 'src/main/java'
         test.java.srcDirs += 'src/test/java'
+        staging.res.srcDirs += 'src/debug/res'
         androidTest.java.srcDirs += 'src/androidTest/java'
     }
     testBuildType "staging"
@@ -44,7 +45,8 @@ android {
 
     buildTypes {
         debug {
-
+                applicationIdSuffix '.debug'
+                versionNameSuffix "-debug"
         }
         staging {
             initWith debug
@@ -74,6 +76,7 @@ android {
             proguardFiles 'proguard-rules.pro'
         }
     }
+
     testOptions {
         animationsDisabled true
 
@@ -86,14 +89,23 @@ android {
     apply plugin: 'kotlin-kapt'
 }
 
+afterEvaluate {
+    /**
+     * Make a string with the application_id (available in xml etc)
+     */
+    android.applicationVariants.all { variant ->
+        variant.resValue 'string', 'application_id', variant.applicationId
+    }
+}
+
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
 
     /**
      * AndroidX dependencies:
      */
-    implementation 'androidx.appcompat:appcompat:1.2.0'
-    implementation 'androidx.core:core-ktx:1.3.2'
+    implementation 'androidx.appcompat:appcompat:1.3.0'
+    implementation 'androidx.core:core-ktx:1.5.0'
     implementation 'androidx.preference:preference-ktx:1.1.1'
     implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
     implementation 'androidx.navigation:navigation-fragment-ktx:2.3.5'
@@ -111,7 +123,7 @@ dependencies {
     implementation "androidx.annotation:annotation:1.2.0"
     implementation 'androidx.gridlayout:gridlayout:1.0.0'
     implementation "androidx.activity:activity-ktx:1.2.3"
-    implementation 'androidx.fragment:fragment-ktx:1.3.3'
+    implementation 'androidx.fragment:fragment-ktx:1.3.4'
 
     // Use the most recent version of CameraX
     def cameraX_version = '1.0.0'
@@ -191,7 +203,7 @@ dependencies {
 
     // debugImplementation required vs testImplementation: https://issuetracker.google.com/issues/128612536
     //noinspection FragmentGradleConfiguration
-    stagingImplementation("androidx.fragment:fragment-testing:1.3.3") {
+    stagingImplementation("androidx.fragment:fragment-testing:1.3.4") {
         exclude group:'androidx.test', module:'monitor'
     }
 
diff --git a/app/src/debug/res/drawable-v24/ic_launcher_foreground.xml b/app/src/debug/res/drawable-v24/ic_launcher_foreground.xml
new file mode 100644
index 00000000..b382f73c
--- /dev/null
+++ b/app/src/debug/res/drawable-v24/ic_launcher_foreground.xml
@@ -0,0 +1,38 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:pathData="M31,63.928c0,0 6.4,-11 12.1,-13.1c7.2,-2.6 26,-1.4 26,-1.4l38.1,38.1L107,108.928l-32,-1L31,63.928z">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:startY="49.59793"
+                android:startX="42.9492"
+                android:endY="92.4963"
+                android:endX="85.84757"
+                android:type="linear">
+                <item
+                    android:color="#44000000"
+                    android:offset="0.0" />
+                <item
+                    android:color="#00000000"
+                    android:offset="1.0" />
+            </gradient>
+        </aapt:attr>
+    </path>
+    <group
+        android:name="foo"
+        android:scaleX="2"
+        android:scaleY="2"
+        android:translateY="0"
+        android:translateX="0">
+    <path
+        android:pathData="M23.0332,30.2725L27.5781,30.2725C31.8595,30.2725 35.3302,26.9088 35.3302,22.7596C35.3302,18.6103 31.8595,15.2467 27.5781,15.2467L21.0185,15.2467C18.5485,15.2467 16.5461,17.1872 16.5461,19.581L16.5461,36.451L23.0332,30.2725Z"
+        android:strokeWidth="1"
+        android:fillColor="#FFFFFF"
+        android:fillType="nonZero"
+        android:strokeColor="#00000000"/>
+    </group>
+</vector>
\ No newline at end of file
diff --git a/app/src/debug/res/drawable/ic_launcher_background.xml b/app/src/debug/res/drawable/ic_launcher_background.xml
new file mode 100644
index 00000000..ca3826a4
--- /dev/null
+++ b/app/src/debug/res/drawable/ic_launcher_background.xml
@@ -0,0 +1,74 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector
+    android:height="108dp"
+    android:width="108dp"
+    android:viewportHeight="108"
+    android:viewportWidth="108"
+    xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#3DDC84"
+          android:pathData="M0,0h108v108h-108z"/>
+    <path android:fillColor="#00000000" android:pathData="M9,0L9,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,0L19,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M29,0L29,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M39,0L39,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M49,0L49,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M59,0L59,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M69,0L69,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M79,0L79,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M89,0L89,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M99,0L99,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,9L108,9"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,19L108,19"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,29L108,29"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,39L108,39"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,49L108,49"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,59L108,59"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,69L108,69"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,79L108,79"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,89L108,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,99L108,99"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,29L89,29"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,39L89,39"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,49L89,49"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,59L89,59"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,69L89,69"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,79L89,79"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M29,19L29,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M39,19L39,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M49,19L49,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M59,19L59,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M69,19L69,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M79,19L79,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+</vector>
diff --git a/app/src/debug/res/mipmap-anydpi-v26/ic_launcher.xml b/app/src/debug/res/mipmap-anydpi-v26/ic_launcher.xml
new file mode 100644
index 00000000..bbd3e021
--- /dev/null
+++ b/app/src/debug/res/mipmap-anydpi-v26/ic_launcher.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background"/>
+    <foreground android:drawable="@drawable/ic_launcher_foreground"/>
+</adaptive-icon>
\ No newline at end of file
diff --git a/app/src/debug/res/mipmap-anydpi-v26/ic_launcher_round.xml b/app/src/debug/res/mipmap-anydpi-v26/ic_launcher_round.xml
new file mode 100644
index 00000000..bbd3e021
--- /dev/null
+++ b/app/src/debug/res/mipmap-anydpi-v26/ic_launcher_round.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background"/>
+    <foreground android:drawable="@drawable/ic_launcher_foreground"/>
+</adaptive-icon>
\ No newline at end of file
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index b848a8d5..ff17319e 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -127,7 +127,7 @@
 
         <provider
             android:name="androidx.core.content.FileProvider"
-            android:authorities="org.pixeldroid.app.fileprovider"
+            android:authorities="${applicationId}.fileprovider"
             android:exported="false"
             android:grantUriPermissions="true">
             <meta-data
diff --git a/app/src/main/java/org/pixeldroid/app/postCreation/PostCreationActivity.kt b/app/src/main/java/org/pixeldroid/app/postCreation/PostCreationActivity.kt
index bda7e7cc..8d7ba739 100644
--- a/app/src/main/java/org/pixeldroid/app/postCreation/PostCreationActivity.kt
+++ b/app/src/main/java/org/pixeldroid/app/postCreation/PostCreationActivity.kt
@@ -39,6 +39,7 @@ import io.reactivex.schedulers.Schedulers
 import okhttp3.MultipartBody
 import retrofit2.HttpException
 import java.io.File
+import java.io.FileNotFoundException
 import java.io.IOException
 import java.io.OutputStream
 import java.text.SimpleDateFormat
@@ -313,7 +314,16 @@ class PostCreationActivity : BaseActivity() {
 
         for (data: PhotoData in photoData) {
             val imageUri = data.imageUri
-            val imageInputStream = contentResolver.openInputStream(imageUri)!!
+            val imageInputStream = try {
+                contentResolver.openInputStream(imageUri)!!
+            } catch (e: FileNotFoundException){
+                AlertDialog.Builder(this).apply {
+                    setMessage(getString(R.string.file_not_found).format(imageUri))
+
+                    setNegativeButton(android.R.string.ok) { _, _ -> }
+                }.show()
+                return
+            }
 
             val imagePart = ProgressRequestBody(imageInputStream, data.size)
             val requestBody = MultipartBody.Builder()
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index ebd8f06c..f77e9206 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -1,7 +1,12 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
+    <!-- Name of the app. In most languages you won't want to change this. -->
     <string name="app_name">PixelDroid</string>
+
+    <!-- Button to go to the user's profile -->
     <string name="menu_account">My Profile</string>
+
+    <!-- Button to go to the settings -->
     <string name="menu_settings">Settings</string>
     <string name="invalid_domain">"Invalid domain"</string>
     <string name="registration_failed">"Could not register the application with this server"</string>
@@ -14,16 +19,35 @@
     <string name="instance_not_pixelfed_continue">"OK, continue anyway"</string>
     <string name="instance_not_pixelfed_cancel">"Cancel logging in"</string>
     <string name="title_activity_settings2">Settings</string>
-    <!-- Theme Preferences -->
+
+    <!-- Theme Preferences: title of button -->
     <string name="theme_title">Application Theme</string>
+
+    <!-- Theme Preferences: title of the settings section dedicated to themes -->
     <string name="theme_header">Theme</string>
+
+    <!-- Theme Preferences: default option (follow the system theme) -->
     <string name="default_system">Default (Follows system)</string>
+
+    <!-- Theme Preferences: light theme option -->
     <string name="light_theme">Light</string>
+
+    <!-- Theme Preferences: dark theme option -->
     <string name="dark_theme">Dark</string>
+
+    <!-- Notifications: follow notification -->
     <string name="followed_notification">%1$s followed you</string>
+
+    <!-- Notifications: mention (@) notification -->
     <string name="mention_notification">%1$s mentioned you</string>
+
+    <!-- Notifications: share (boost) notification -->
     <string name="shared_notification">%1$s shared your post</string>
+
+    <!-- Notifications: like (favourite) notification -->
     <string name="liked_notification">%1$s liked your post</string>
+
+    <!-- Notifications: end of poll notification -->
     <string name="poll_notification">"%1$s's poll has ended"</string>
 
     <!-- Login page -->
@@ -201,4 +225,7 @@ For more info about Pixelfed, you can check here: https://pixelfed.org"</string>
     <string name="mascot_description">Image showing a red panda, Pixelfed\'s mascot, using a phone</string>
     <string name="delete_post_failed_error">Could not delete the post, error %1$d</string>
     <string name="delete_post_failed_io_except">Could not delete the post, check your connection?</string>
+
+    <!-- Error message when a selected file can not be found -->
+    <string name="file_not_found">File %1$s was not found</string>
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/xml/root_preferences.xml b/app/src/main/res/xml/root_preferences.xml
index 2ffb30f9..298a62a6 100644
--- a/app/src/main/res/xml/root_preferences.xml
+++ b/app/src/main/res/xml/root_preferences.xml
@@ -26,7 +26,7 @@
         android:summary="@string/about_pixeldroid"
         app:icon="@drawable/info_black_24dp">
         <intent
-            android:targetPackage="org.pixeldroid.app"
+            android:targetPackage="@string/application_id"
             android:targetClass="org.pixeldroid.app.settings.AboutActivity"/>
     </Preference>
 </PreferenceScreen>