JSFiddle - React, Tailwind, and code Playground

HTML

<div class="header__login">
  <a href="#" class="login__vk">Войти через<img class="login__vk-pic" src="http://s32.postimg.org/l7ulie6yp/image.png" alt=""></a>
</div>

CSS

.header__login {
  width: 40%;
  height: 50px;
  border: 1px solid;
  position: relative;
  
  text-align: center;
}

.header__login::before {
  content: '';
  
  display: inline-block;
  vertical-align: middle;
  
  height: 100%;
}