I tried searching for this, but there's a different feature in SublimeText that people call "preview", so I couldn't find any relevant info.
How do I disable the preview navigation image that's displayed within SublimeText2 when a document is open? Also, what is this feature called?
This is called the "Minimap" in Sublime Text. To disable it, go to View -> Hide Minimap
in the menus.
If you'd like a keyboard shortcut to toggle this, you can create one by adding this:
{ "keys": ["ctrl+k", "ctrl+m"], "command": "toggle_minimap" }
...to your Preferences -> Key Bindings - User
file. This sets it to the sequence Ctrl+K followed by Ctrl+M, which I chose just because it's similar to the shortcut (Ctrl+K, Ctrl+B) which toggles the sidebar, but you can set it to whatever you like.