run("Close All");
for(num=1; num <=6; num++){
   title = "Img_" + num;
   newImage(title, "8-bit ramp", 800, 600, 1);

}
print("\\Clear");
for(loop = 1; loop <= 3; loop++){
   print(loop);
   for(num=1; num <=6; num++){
      title = "Img_" + num;
      time = getTime;
      selectImage(title);
      print(title,  getTitle, "time[ms]: ", getTime-time);
   }
}