Photoshop script to open next numbered file in sequence with saving.

Open next file.jsx

var folderPath = activeDocument.path
var filePieces = activeDocument.name.split('.');
var fileName = filePieces[0];
var fileExtension = filePieces[1];
// We need to unpad the string for some reason, otherwise PS-JS
// thinks it's a past layer some times when using parseInt. 
fileNameStart = 0;
for (var i = 0; i < fileName.length - 1; i++) {
    digit = fileName[i];
    if (digit == '0') {
        fileNameStart++;
    } else {
        break
    };
}
fileNameUnpadded = fileName.slice(fileNameStart);
var nextFileNumber = parseInt(fileNameUnpadded) + 1;
// Yes it's haxxy I know...
var padTemp = ("000000000000000" + nextFileNumber.toString());
var nextFileName = padTemp.slice(padTemp.length - 5);
var nextFilePath = folderPath + '/' + nextFileName + '.' + fileExtension;
activeDocument.close(SaveOptions.SAVECHANGES);

try {
    var docRef = open(new File(nextFilePath));
}
catch (e) {
    alert("No more files in the directory!");
}