SVG Gradient Mask on image

HTML

<div style="background-color:black">
<svg viewBox="0 0 533 300" style="width:100%;">
            <defs>
             <linearGradient id="gradient" x1="0" x2="0" y1="0" y2="1">
               <stop offset="0.75" stop-color="white" stop-opacity="1" />
               <stop offset="1" stop-color="white" stop-opacity="0" />
             </linearGradient>

             <mask id="gradient-mask">
               <rect x="0" y="0" width="533" height="300" fill="url(#gradient)"  />  
             </mask>
            </defs>

            <image mask="url(#gradient-mask)" width="533" height="300" y="0" x="0" xlink:href="https://www.gravatar.com/avatar/563ab82d4f106574e5640e1621cfbf05?s=80" />
          </svg></div>