Blackbam

Create, manage and view snapshots of any post (or custom post type) whenever you want. Like user-managed revisions with a lot of useful functionality.
Features: 
* Create snapshots of any post type including all metadata at any point manually as a secure history and backup of your posts 
* Uses the standard WordPress posts table (like revisions) 
* Uses a custom post status (and therefore works for any post type) 
* Easy snapshot management meta box 
* Create Snapshots comfortably in the publish post box 
* Choose which post types you want to enable the snapshots feature for
PHP Developer API: 
 pos_create_snapshot_from($post_id): Creates a new snapshot for a given post ID 
 pos_delete_snapshot($snap_id): Delete a snapshot by its ID 
 pos_get_latest_snapshot($post_id): Returns the ID of the latest snapshot for a given post ID 
 pos_get_plainview_url($snap_id): Get the URL to the plain snapshot view
This Plugin is sponsored by ready2order GmbH, the company which is producing Austria’s best point-of-sale system. Visit us at https://www.ready2order.com/.
NOTE: The use of a custom post status in WordPress is still in beta. The developers of this plugin are in no possible case responsible for any data loss. 
If you want to be sure nothing happens, backup your database on a regular basis. You should do it anyway.

Post Snapshots

Everything works as expected and I did not hear any compaints yet.

On our live website it has been working great since two months now

Create, manage and view snapshots of any post (or custom post type) whenever you want. Like user-managed revisions with a lot of useful functionality.

Francis

The aim of this plugin is to display a thumbnail when hovering over a link in the blog posts.
Thumbnails are generated by the Apercite service ( http://www.apercite.fr/en/ ). The thumbnail is generated in 20 seconds. 
You can choose the thumbnail size between 19 predefined sizes. You also have the ability to enable or disable JavaScript and Java when generating the thumbnail.
If you have a valid subsciption to the Apercite service, you can fill in you login and API key to request the update of the thumbnails. To do so, you need to tick the box in the edition interface of each post.
Feel free to contact me if you need help in finding the appropriate CSS attributes to display the thumbnails on your blog (don’t forget to mention the blog URL).

Apercite

The aim of this plugin is to display a thumbnail when hovering over a link in the blog posts.

Post Snapshots vs Apercite