Ionic v2 how to insert a logo in header

    <ion-header>

  <ion-navbar>
    <ion-title>
<img alt="logo" height="40"   src="img/logo.png" > 
</ion-title>
  </ion-navbar>

</ion-header>

Headers in Ionic have a height of 44px. So, you need to make sure the logo is sized less than that.

.title-image {
    margin-top: 8px;
    height: 27px;
}