title: Canvas toBlob quality
body: <p>Our app takes canvas content and then display it as thumbnail with max-height of 150px</p>
  
  <p>canvas can be as large as the monitor, for now lets pick 2560x1440</p>
  
  <p>If converting to webp, </p>
  
  <p>is there an equation to get quality number that roughly preserve image quality ? , maybe</p>
  
  <pre><code>targetHeight = 150
  originalHeight = 1440
  
  quality = targetHeight / originalHeight 
  // 150px / 1440px ~ 0.1 ?
  
  canvas.toBlob((blob) =&gt; {
  
      const currentScreenshot = URL.createObjectURL(blob);
  
  }, "image/webp", quality);
  </code></pre>