Как изображение сделать ссылкой

a { 
  position: relative; 
  display: block; 
  width: 100px; 
  height: 100px; 
} 
 
img { 
  position: absolute; 
  display: block; 
  width: 100px; 
  height: 100px; 
}

<a href="https://yandex.ru" target="_blank"><img src="https://is4-ssl.mzstatic.com/image/thumb/Purple71/v4/07/cb/fc/07cbfcc0-ac70-8fb3-0ae8-6ba4648d58f2/pr_source.png/100x100bb-85.jpg"></a>

document.querySelector('img').addEventListener('click', function() { 
  window.open('https://ya.ru', '_blank'); 
})

img { 
  position: absolute; 
  display: block; 
  width: 100px; 
  height: 100px; 
}

<img src="https://is4-ssl.mzstatic.com/image/thumb/Purple71/v4/07/cb/fc/07cbfcc0-ac70-8fb3-0ae8-6ba4648d58f2/pr_source.png/100x100bb-85.jpg">