//main.js
var folderName="images"; // images folder of filesystem is used
function onsuccess(files) {
    	   for (var i = 0; i < files.length; i++) {
    	     if (files[i].isDirectory == false){
    	    	 var fields = files[i].fullPath.split('.');
    	    	 var extType=fields[1];
    	    	 if(extType === 'png'){
    	    		 console.log(files[i].fullPath);
    	    	 }
    	     }
    	   }
    	 }
    	 function onerror(error) {
    	   console.log("The error " + error.message + " occurred when listing the files in the selected folder");
    	 }
    var mainPage = document.querySelector('#main');
    mainPage.addEventListener("click", function() {
    	  console.log("Page Init");
		   var documentsDir;
	    	 tizen.filesystem.resolve(folderName, function(dir) {
	    	       documentsDir = dir;
	    	       dir.listFiles(onsuccess,onerror);
	    	     }, function(e) {
	    	       console.log("Error" + e.message);
	    	     }, "rw"
	    	 );
    });
    
    
// config.xml
<tizen:privilege name="http://tizen.org/privilege/filesystem.read"/>
<tizen:privilege name="http://tizen.org/privilege/filesystem.write"/>