Example of plugin to swap out an image to point left or right as the user clicks the "link"

main.js

//Example of file using it
$(document).ready(function () {
  $('h2').on('click', function(){
    	var location = window.location.origin;
    	var url = "/sites/all/themes/chroma-blue/images"; 
    	var down = "down.jpg";
    	var right = "right.jpg";
      //Look in plugins.js
    	$(this).arrow({
    		location: location,
    		url: url,
    		down: down,
    		right: right
  	});
});

plugin.js

(function($) {
$.fn.arrow = function(options){
	var settings = $.extend({
		location: window.location.origin,
		url: '/sites/all/themes/chroma-blue/images',
		down: 'down.jpg',
		right: 'right.jpg'
	});
	if( $(this).css('background-image') === 'url('+settings.location+settings.url+'/'+settings.down+')' ) {
		$(this).css('background-image', 'url("'+settings.url+'/'+settings.right+'")');
	} else {
		$(this).css('background-image', 'url("'+settings.url+'/'+settings.down+'")');
    }
    return this;
};
}(jQuery));