I'm guessing Dio simply specified a height in the html code that was larger than the normal height of the picture.
When you're doing your html for a picture you an do it simple like-
img src="url address"
or you can go-
img height=800 src="url" (or whatever size you want the height to be)
You haven't really blown the picture up- you've instructed the browser to display the picture in a bigger area than it would if it simply loaded at its true size. What's really annoying is when people make thumbnails like this. They haven't lost any of the file size even though the picture looks smaller. You simply have 20 (or whatever) full sized images loaded into little areas- no speed gained.