diff --git a/app/app.iml b/app/app.iml
index 5a074cf1..f9f7358b 100644
--- a/app/app.iml
+++ b/app/app.iml
@@ -70,13 +70,6 @@
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/java" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/rs" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/shaders" isTestSource="true" />
-      <sourceFolder url="file://$MODULE_DIR$/src/test/res" type="java-test-resource" />
-      <sourceFolder url="file://$MODULE_DIR$/src/test/resources" type="java-test-resource" />
-      <sourceFolder url="file://$MODULE_DIR$/src/test/assets" type="java-test-resource" />
-      <sourceFolder url="file://$MODULE_DIR$/src/test/aidl" isTestSource="true" />
-      <sourceFolder url="file://$MODULE_DIR$/src/test/java" isTestSource="true" />
-      <sourceFolder url="file://$MODULE_DIR$/src/test/rs" isTestSource="true" />
-      <sourceFolder url="file://$MODULE_DIR$/src/test/shaders" isTestSource="true" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/assets" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/blame" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/classes" />
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 46754a9d..3e9a2678 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -140,11 +140,18 @@
                 android:resource="@xml/syncadapter" />
         </service>
 
+        <!--Generates a FileProvider class for the app with the appropriate authority.
+        This allows the system to securely share files by creating content URI for files rather than file URI,
+        thus granting temporary file access permissions to sharing apps.
+        This is required for devices with Android M or above, while it wasn't necessary before. Without a file provider class,
+        the OS will deny other apps the permission to access GalaxyZoo's files, and sharing locally stored images will be impossible-->
         <provider
             android:name="android.support.v4.content.FileProvider"
             android:authorities="@string/authority_fileprovider"
             android:exported="false"
             android:grantUriPermissions="true">
+            <!--This meta data and the associated XML file specify that the files will be written to the root folder
+            of the app's external storage area-->
             <meta-data
                 android:name="android.support.FILE_PROVIDER_PATHS"
                 android:resource="@xml/provider_paths"/>
diff --git a/app/src/main/java/com/murrayc/galaxyzoo/app/ClassifyFragment.java b/app/src/main/java/com/murrayc/galaxyzoo/app/ClassifyFragment.java
index a75c77ad..0416f366 100644
--- a/app/src/main/java/com/murrayc/galaxyzoo/app/ClassifyFragment.java
+++ b/app/src/main/java/com/murrayc/galaxyzoo/app/ClassifyFragment.java
@@ -24,7 +24,6 @@
 import android.database.Cursor;
 import android.net.Uri;
 import android.os.Bundle;
-import android.support.annotation.Nullable;
 import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentManager;
 import android.support.v4.app.FragmentTransaction;
diff --git a/app/src/main/java/com/murrayc/galaxyzoo/app/SubjectFragment.java b/app/src/main/java/com/murrayc/galaxyzoo/app/SubjectFragment.java
index e0823b21..23c7b09b 100644
--- a/app/src/main/java/com/murrayc/galaxyzoo/app/SubjectFragment.java
+++ b/app/src/main/java/com/murrayc/galaxyzoo/app/SubjectFragment.java
@@ -19,6 +19,8 @@
 
 package com.murrayc.galaxyzoo.app;
 
+import android.*;
+import android.Manifest;
 import android.app.Activity;
 import android.app.DownloadManager;
 import android.content.Context;
@@ -438,6 +440,11 @@ private void updateShareActionIntent() {
         //shareIntent.putExtra(Intent.EXTRA_STREAM, mUriImageStandard);
         //shareIntent.setType("image/*");
 
+        /**
+         * if the image URI is not null, a GetImageBitmapAsyncTask is executed for it, and the returned URI is set as
+         * a stream extra on the intent that will be shared, along with an explicit permission for recieving contexts to
+         * read the content URI, enabling them to access the generated image.
+         */
         if (mUriStandardRemote!=null) {
             GetImageBitmapAsyncTask getImageBitmapAsyncTask = new GetImageBitmapAsyncTask(){
                 @Override
@@ -451,18 +458,20 @@ protected void onPostExecute(Uri uri) {
             getImageBitmapAsyncTask.execute(mUriStandardRemote);
         }
 
-
-        mShareActionProvider.setShareIntent(shareIntent);
     }
 
+    /**
+     *These constants and the verifyStoragePermissions method will gain explicit permission from users to read and write
+     * files on their devices. This will allow us to save an image, that can then be shared to other apps.
+     */
     private static final int REQUEST_EXTERNAL_STORAGE = 1;
     private static String[] PERMISSIONS_STORAGE = {
-            "android.permission.WRITE_EXTERNAL_STORAGE",
-            "android.permission.READ_EXTERNAL_STORAGE"
+            Manifest.permission.WRITE_EXTERNAL_STORAGE,
+            Manifest.permission.READ_EXTERNAL_STORAGE
     };
 
     public static void verifyStoragePermissions(Activity activity) {
-        int permission = ActivityCompat.checkSelfPermission(activity, "android.permission.WRITE_EXTERNAL_STORAGE");
+        int permission = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE);
 
         if (permission != PackageManager.PERMISSION_GRANTED) {
             ActivityCompat.requestPermissions(
@@ -473,7 +482,13 @@ public static void verifyStoragePermissions(Activity activity) {
         }
     }
 
-    private class GetImageBitmapAsyncTask extends AsyncTask<String,Integer,Uri> {
+    /**
+     * This AsyncTask, when executed, takes a String that represents a URI, creates the appropriate Bitmap, saves it to
+     * the external storage area of the app as a jpg, and returns the content Uri of that file as generated by the FileProvider class.
+     * Keeping a single file name ensures that future tasks will write over images previously generated by this task instead
+     * of creating new ones.
+     */
+    private class GetImageBitmapAsyncTask extends AsyncTask<String, Integer, Uri> {
         @Override
         protected Uri doInBackground(String... params) {
             try {
@@ -481,7 +496,6 @@ protected Uri doInBackground(String... params) {
                 ByteArrayOutputStream bytes = new ByteArrayOutputStream();
                 image.compress(Bitmap.CompressFormat.JPEG, 100, bytes);
 
-                //TODO: PROVIDE A MORE DESCRIPTIVE FILENAME HERE IF PLAUSIBLE. Filename will be visible when sharing via certain apps like Gmail etc.
                 String filename = "galaxy_zoo_image.jpg";
 
                 String pathname = Environment.getExternalStorageDirectory() + File.separator + filename;
diff --git a/app/src/main/res/xml/provider_paths.xml b/app/src/main/res/xml/provider_paths.xml
new file mode 100644
index 00000000..5aafec20
--- /dev/null
+++ b/app/src/main/res/xml/provider_paths.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<paths xmlns:android="http://schemas.android.com/apk/res/android">
+    <!--The FileProvider class will draw from the root directory of the app's external storage area (specified by path="."),
+    and the generated content URI will indicate that this directory is called "external_files" for security reasons.-->
+    <external-path name="external_files" path="."/>
+</paths>
\ No newline at end of file