add pictures

Author: willdurand

src/images/instapaper.png

@@ -21,13 +21,18 @@ experience](https://www.instapaper.com/help),
 as Read It Later, and [Wallabag](https://www.wallabag.org/), the Open Source
 alternative.
 
+![](../images/instapaper.png)
+
 In order to build a Minimum Viable Product (MVP), a Read It Later application
 has to:
 
 * save links a single user wants to _read later_;
 * fetch the content of a link to enable offline mode (content has to be stored);
+* mark a link as _archived_ (or _read_) when a user has read it;
 * provide the ability to sort links into categories.
 
+![](../images/instapaper_2.png)
+
 Ideally, fetching the content of a link SHOULD be done with a **worker**. A
 worker is a special application that runs periodically (e.g., every _X_
 minutes), and loops over a set of tasks to perform. For instance, it can