Awesome Background Image Slider Plugin for WordPress which creates fullscreen image slideshows inside your WordPress Site Background.
You can set the directory to whatever you like, it is based from your WebSite root folder. So specifying 'images/slides' as an image location means that your images should be located for example as 'http://[YOUR SITE]/images/slides/image.jpg'. The default folder does not exist on setup, you will need to create it or set your own folder location.
Images are read by the Plugin from the specified image folder location. All you have to do is optimize and place your images in that folder.
Main cause of this usually is the jQuery / CSS files are not being loaded, returning a 404 not found error; check the paths in your setup (Best done using Firebug or a live code editor) For example, your site should be able to see this: http://YOUR SITE]/wp-content/plugins/site-background-slider/assets/jquery.min.js
If the file is there, but still cannot be read, check the folder permissions (should be readable, 755). Lastly also make sure your filename has no weird characters (For example ö, ü, ä, etc).
This plugin has its own wiki documentation available at Press Pixels. Check it out for more answers!