navbar brand image must be sized and the structure should look like this

<nav class="navbar navbar-expand-lg navbar-dark bg-dark">
        <a class="navbar-brand" href="#">
            <img src="https://getbootstrap.com/docs/4.4/assets/brand/bootstrap-solid.svg" width="30" height="30"
                class="d-inline-block align-top" alt="">
            Bootstrap
        </a>
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent"
            aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
        </button>

        <div class="collapse navbar-collapse" id="navbarSupportedContent">
            <ul class="navbar-nav mr-auto">
                <li class="nav-item active">
                    <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="#">Link</a>
                </li>
                <li class="nav-item dropdown">
                    <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button"
                        data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                        Dropdown
                    </a>
                    <div class="dropdown-menu" aria-labelledby="navbarDropdown">
                        <a class="dropdown-item" href="#">Action</a>
                        <a class="dropdown-item" href="#">Another action</a>
                        <div class="dropdown-divider"></div>
                        <a class="dropdown-item" href="#">Something else here</a>
                    </div>
                </li>
                <li class="nav-item">
                    <a class="nav-link disabled" href="#" tabindex="-1" aria-disabled="true">Disabled</a>
                </li>
            </ul>
            <form class="form-inline my-2 my-lg-0">
                <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
                <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
            </form>
        </div>
    </nav>

this is my code:

<nav class="navbar navbar-expand-md navbar-dark bg-dark sticky-top">
<div class="container-fluid">
    <a class="navbar-brand" href="#"> <img src="https://i.stack.imgur.com/5XeYV.png" width="225" height="245"> </a>
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarResponsive">

    </Button>
</div>
</nav>

this is what shows:
Click here to see what it shows

help would be appreciated thanks