An external editor is an application outside of MediaWiki or your browser that can be used to edit text or images on your wiki. When enabled, you can choose to edit text in an application such as vi, OpenOffice Writer, or Microsoft Word, or to edit images in packages such as PaintShop Pro, GIMP, Photoshop -- the options are limitless.
If you install this feature, you will be able to save data to Wikia directly from any editing program, along with an edit summary. You will be able to make multiple edits on the server by using the "save and continue" button.
How do I enable external editing?
This feature requires you to install a helper application called "ee.pl" which can be downloaded from Wikimedia site.
Ee.pl can also be used to view diffs using an external diff program instead of the MediaWiki diff feature. See MetaWikipedia:Help:Diff.
How do I use external editing?
For images, there is always a link on the image description page which lets you choose to edit the image externally.