Editors (with capital E) are users (Contributors) with a few special rights, most importantly the right to upload images. See the page "Users and Rights" for more information about various kinds of users and their rights. (Note that an 'editor' without capital E is anyone who makes an edit to a Geopoeia page.)
Active users (Contributors) can request to become an Editor in the "Site issues and suggestions" forum. With that request, it must be stated explicitly that the image guidelines and other key site policies are read and understood. An Editor violating the image guidelines or other site policies may lose his/her Editor status.
see also: list of users with 'Editor' status