Processing of recent images in a folder which contains old images also?

You could give this a try (it uses the modified-property, if you want to use created just change line 13 accordingly):

// get the newest file/s from a folder;
// 2011, use it at your own risk;
var theFolder = Folder.selectDialog ("select folder");
if (theFolder != null) {
// set the number of the most recent files to get;
var theNumber = 2;
// get the files;
var theFiles = theFolder.getFiles(/\.(jpg|tif|eps|psd)$/i);
var modifiedDate = new Array;
var theNewest = new Array;
for (var m = 0; m < theFiles.length; m++) {
          var theFile = theFiles;
          modifiedDate.push( [theFile, File(theFile).modified.getTime()] )
          };
// sort by date;
modifiedDate.sort(sortByDate);
for (var n = 0; n < theNumber; n++) {
          theNewest.push(modifiedDate[0])
          };
alert ("the "+theNumber+" most recently changed files are\n"+theNewest.join("\n"));
};
////// to sort a double array by sam, http://www.rhinocerus.net/forum/lang-javascript/ //////
function sortByDate(a,b) {
if (a[1]<b[1]) return -1;
if (a[1]>b[1]) return 1;
return 0;
};