Menu items no longer show up – Can’t add or remove watermarks

Image Watermark has been working for a long time, but I just noticed that it no longer shows up in the media library menus, or when editing an image. I am unable to add or remove any watermarks at this point. Existing watermarks continue to be displayed. I am on the most recent version of the plugin (1.6.6), and WordPress 5.3.2. I’ve tried re-applying settings, and de-activating/re-activating the plugin.