Clarify permissions usage

Author: shekibobo

README.md

@@ -36,16 +36,20 @@ If you are using maven to manage your project, add the following to your `pom.xm
 
 ### Step 2
 
-Add permissions (if necessary) to your `AndroidManifest.xml`:
+Add permissions (if necessary) to your `AndroidManifest.xml`
 
 ```xml
 <!-- if you want to load images from the internet -->
 <uses-permission android:name="android.permission.INTERNET" /> 
 
-<!-- if you want to load images from external storage -->
+<!-- if you want to load images from a file OR from the internet -->
 <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
 ```
 
+**Note:** If you want to load images from the internet, you need both the `INTERNET` and `READ_EXTERNAL_STORAGE` permissions to allow files from the internet to be cached into local storage.
+
+If you want to load images from drawable, then no additional permissions are necessary.
+
 ### Step 3
 
 Add the Slider to your layout: