You can't import images using CSV import plugin, but you can import them separately using the
IMGByID utility.
For the utility to work first import your movies without images, then set IDs for all the movies (Tools -> Reindex movies) in the database, then name your image file, so that the filename is id.extension or somename_id.extension, then run the utility.
Another approach would be: importing your titles with year and then getting posters using amazon plugin (or another poster import plugin) with Silent mode checked in tools -> preferences -> plugins. Note laos that you can configure the IMDB plugin to get images as well, as you will probably need to run it for all the movies to get all the fields filled.