URL for nivo slider images broken on all pages except front page

When editing the images used for the Nivo-slider I decided to put the images in the drupal root.

This works ok, for the front page.

However, when following a link to say www.example.com/node/1, the URL for the image Nivo-slider tries to display becomes www.example.com/node/slideshow1.jpg, whereas it should be www.example.com/slideshow1.jpg in order to display properly.

I've tried looking in the accompanying .js-files, but doesn't possess the required skill level to debug this error.