Why is it not working?

I am trying to insert images into WP_Flexgrid and editing the code as detailed but the images are not showing on the page as expected. What I am getting is a placeholder for the image but no image. I have tried 2 different settings as shown below but neither display the image as expected. Can anyone help with the solution.
Web site: http://www.bilking.uk/c7

<div class="flex_row">
<div class="flex_item"> <img src="http://bilking.uk/wp-content/uploads/2016/02/scan_1.jpg"> </div>

<div class="flex_item"> <img src="http://localhost/wordpress/wp-content/plugins/wpflexgrid/inc/images/scan_1.jpg"> </div>

Many thanks

https://wordpress.org/plugins/wpflexgrid/