function CheckExtension(radUpload, eventArgs)
{
    var input = eventArgs.get_fileInputField();
    if (!radUpload.isExtensionValid(input.value))
    {
        var inputs = radUpload.getFileInputs();
        for (i = 0; i < inputs.length; i++)
        {
            if (inputs[i] == input)
            {
                alert(input.value + " is not a valid photo file. Please upload a photo with a JPEG, GIF, or PNG file extension.");
                radUpload.clearFileInputAt(i);
                break;        
            }
        }
    }
}