ATTENTION: There is now a Deck Editor plugin which will download and install card images without the need of additional image pack downloads. The following image pack download links are provided as an archived secondary source in the event the plugin stops working.
To install the MTG Game Definition, add the OCTGN Game Directory to your list of Game Feeds. Paste this URL into the ‘Add Feed’ window inside Games Manager: https://www.myget.org/f/octgngamedirectory
These are the image packages you need in order to view the actual card images in-game.
All sets prior to Return to Ravnica Block – This is a magnet link to a Torrent, which should automatically load your default Torrent client when you click it. Currently, torrenting is the only method to obtain these older images due to its large size (~4 GB). THE IMAGES ARE ORGANIZED BY BLOCKS!
Additional image packs not in the torrent (direct downloads):
Tokens Update Pack 2 (updated September 6, 2013) — adds tokens to all sets prior to Return to Ravnica. Newer sets come pre-bundles with tokens.
Planes & Schemes Update Pack 1 NOTE: Install this pack AFTER you install the Torrent packs. Updates planes & schemes cards to appear larger in-game and rotated properly.
Return to Ravnica Block Bundle – Includes Return to Ravnica, Gatecrash, Dragon’s Maze, M14 Modern Masters, FTV 20, Sorin vs Tibalt, Heroes vs Monsters
Theros Block Bundle – Includes Theros, Born of the Gods, Journey To Nyx, M15, Modern Event Deck, Speed vs Cunning, Jace vs Vraska, FTV Annihilation, Theros Challenge Decks, Vintage Masters, Conspiracy, Commander 2013
Khans of Tarkir Bundle – Includes Khans of Tarkir, Fate Reforged, Dragons of Tarkir, Magic Origins, FTV Angels, Commander 2014, Elspeth vs Kiora, Zendikar vs Eldrazi, Tempest Remastered, Modern Masters 2015
Special thanks goes out to the folks at http://www.slightlymagic.net for their amazing high-resolution card scans!