title: What the visual difference between DPR: 1.0, DPR: 2.0, DPR: 3.0 for human eyes?
body: <p>For example :</p>
  
  <p>I have thumbnail of image in fixed size block 250x250px. 
  And three images:</p>
  
  <pre><code>&lt;img sizes  = "250px"
       src    = "image-250w.jpg" 
       srcset = "image-250w.jpg 250w,
                 image-500w.jpg 500w,
                 image-750w.jpg 750w"
  &gt;
  </code></pre>
  
  <p>So browser pick candidate 250w for device with DPR: 1.0, 500w for device with DPR: 2.0 and 750w for device with DPR: 3.0. </p>
  
  <p><strong>So what the visual difference between these DPR 1,2,3 for human eyes?</strong></p>
  
  <p>I don't have devices(iPhone, etc.) with different DPR to see this. And device emulations can't show me this while I do it on same display.</p>