This editor is using the new Image (image2) plugin, which implements a dynamic click-and-drag resizing
and easy captioning of the images.
To use the new plugin, include it in config.extraPlugins
parameter and remove the old one (image) with
config.removePlugins (with dependencies).
CKEDITOR.replace( 'textarea_id', {
extraPlugins: 'image2',
removePlugins: 'image'
} );