When you are editing your Drupal site, there will be some custom content types that are controlled by views, and not readily available with an edit button. Often image rotations and galleries will fit into this description. To find content that is not directly editable on a page, try using the Content section to edit.
In the admin menu, the top-level menu item "content" will take you to all of the site content.
Once you click on the content button you will be given the option to filter the content by type:
Once the content is filtered, the item you are looking for should appear in the list and you can edit by selecting the "edit" link that appears in the row.
To search for another page, or reset the filter, simply click reset.