スクロール方向で伸縮するヒーロー画像

<div class="d08-13-01-stage">
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            <div class="d08-13-01-img"></div>
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          <div class="d08-13-01-scroll">
            <div class="d08-13-01-body">
              <p>↓ 下スクロールで画像が縮小 / ↑ 上スクロールで拡大</p>
              <div class="d08-13-01-block"></div>
              <div class="d08-13-01-block"></div>
              <div class="d08-13-01-block"></div>
              <div class="d08-13-01-block"></div>
            </div>
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        </div>

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