Image doesn't show after deploying to device

Hello guys, I am trying to put an image in the nav-bar. It’s working good on the ionic serve but when I deploy on a device, the image doesn’t show. The images are in src/assets/imgs. I have another pictures there as well which are showing after deploying. So the problem would be something in the navbar.

    <button ion-button menuToggle>
      <ion-icon name="menu"></ion-icon>
    <img id="header" src="assets/imgs/pleventz.png" alt="header">
    <ion-buttons end>
      <button ion-button icon-only id="account">
        <ion-icon name="person"></ion-icon>