for num in 1..300 do print("<img src=\"http://path/to/image", format("%03d", num), ".jpg\" />\r") end Output: <img src="http://path/to/image001.jpg" /> <img src="http://path/to/image002.jpg" /> <img src="http://path/to/image003.jpg" /> <img src="http://path/to/image004.jpg" />