How to have img same size as div - css

Question

I want to make a nav bar in the footer with images. The footer needs to be 10% of the total screen and the images need to be within those 10% as well. Only I don't get the images scale according to the screen size and are way bigger. What am I doing wrong?
I am using Bootstrap 4 and I intent to make a mobile version of my website but it is not displaying good.
<div class="footer navbar row">
<div class="col-sm-2 menu_item">
<a href="#home" class="active">
<img src="<source>" class="menu_img" alt="Logo"/>
</a>
</div>
<div class="col-sm-2 menu_item">
<a href="#news">
<img src="<source>" class="menu_img" alt="Logo"/>
</a>
</div>
<div class="col-sm-2 menu_item">
<a href="#contact">
<img src="<source>" class="menu_img" alt="Logo"/>
</a>
</div>
<div class="col-sm-2 menu_item">
<a href="#contact">
<img src="<source>" class="menu_img" alt="Logo"/>
</a>
</div>
<div class="col-sm-2 menu_item">
<a href="#contact">
<img src="<source>" class="menu_img" alt="Logo"/>
</a>
</div>
/* Place the navbar at the bottom of the page, and make it stick */
.navbar {
background-color: var(--primary-color-1);
overflow: hidden;
position: fixed;
bottom: 0;
width: 100%;
margin: 0px;
height: 10vh;
}
/* Style the menu blocks */
.menu_item {
position: relative;
padding: 2px 10px;
margin: 0px;
}
/* Style the links inside the navigation bar */
.navbar a {
float: left;
display: block;
text-align: center;
text-decoration: none;
}
/* Style the images/icons of the links */
.menu_img {
height:100%;
width: 100%;
object-fit: cover;
}

Answer 1

responsive img's need width: 100%; to be responsive, you can control the image size with his container, for example:
<div class="img-container">
<img src="imgUrl"/>
</div>
img{
width: 100%;
}
.img-container{
width: 10%;
}

Answer 2

I found the solution. My structure is like
<div class="footer">
<div>
<a>
<img>
</a>
</div>
</div>
The footer div needs to be height:10%. But I need to set the height of all the other elements to 100%(which I didn't do before). Otherwise it will extend outside those. 'borders'