title: Why Safari on iPad doesn't show large jpeg enclosed in IMG tag?
body: <p>Last time I saw someone asks why Safari on iPad doesn't show some 1920x1440 jpeg with real size &amp; I solved that puzzle. You have to use a <strong>progressive-encoded jpeg</strong>. However, I find another different problem.</p>
  
  <p>Say, demo.jpg is a progressive-encoded jpeg with 2000x3000 &amp; I upload it to my website. I then access it via url ...demo.jpg, Safari will show it with 2000x3000 size, perfect.</p>
  
  <p>Now I make a most-simple html file named mypic.html. This html has only <strong>img tag with  src=demo.jpg</strong> or <strong>src=demo.jpg width=2000 height=3000</strong> inside body. Now I access it via url ...mypic.html. This time Safari show a very small icon of a question mark?</p>
  
  <p>Does anybody know why the latter case fail?</p>