I don't get what I am doing wrong

I was trying yesterday to make the testimonial side by side with each other and the mission and vision statements stay at the bottom but I couldn’t get it right and so I left it and now today, I went there and the images are no more showing, I don’t understand why, I need help. The HTML/CSS are below.
HTML

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="about.css" type="text/css">
    <title>About</title>
</head>
<body>
    <div class="container">
        <div class="menubar">
            <h2>About us</h3>
            <li>Microsoft</li>
            <li>Programming</li>
            <li>Web Designing</li>
            </div>
        <div class="statements">
            <h4>Our Mission statement</h4>- <p>To raise future developers that will rule the world.</p>       
            <h4>Our Vision statement</h4>- <p>Anyone can become a programmer if you put your mind to it and <br>you work hard.</p>
        </div>  
        <div class="Testimonials">
            <h3>Testimonials</h3>
                <img src="Images/Tst1.JPG">
                <img src="Images/Tst2.JPG">
        </div>
        <div class="social media">
                <a href="#"><i class="fa icons fa-facebook"></i></a>
                <a href="#"><i class="fa icons fa-instagram"></i></a>  
                <a href="#"><i class="fa icons fa-twitter"></i></a>
        </div>
    </div>
</body>
</html>

CSS

*{
    margin: 0;
    padding: o;
    font-family: 'Poppins', sans-serif;
}
.container{
    height: 100vh;
    width: 100%;
    background-image: linear-gradient(rgba(0,0,0,0.85)), url(images/Bg1.JPG);
    background-color: aqua;
    background-position: center;
    background-size: cover;
    position: relative;
    box-sizing: border-box;
    padding-right: 5%;
    padding-left: 3%;
}
.menubar{
    width: 100%;
    height:15vh;
    margin: auto;
    display: flex;
    align-items: center;
    border: #ffbd59;
}
h2{
    color: #ffbd59;
    text-transform: uppercase;
    font-weight: 700;
    font-size: 20px;
    margin-top: 10px;
}
nav{
    flex: 1;
    padding-left: 400px;
}
nav ul li{
    display: inline-block;
    list-style: none;
    margin: 0 15px;
}
nav ul li a:hover{
    color:#ffbd59;
}
.statements{
    justify-content: flex-end;
 }
h3{
    color: #ffbd59;
}
p{
    font-size: 15px;
    font-weight: 500;
    line-height: 20px;
    letter-spacing: .1em;
    margin-top: 40px;
}
.btn{
    background: linear-gradient(to right, transparent 50%, #ffbd59 50%);
    background-size: 200% auto;
    background-position: left;
    margin-top: 70px;
    margin-left: 50px;
    padding: 15px 45px;
    text-align: center;
    border: 2px solid #ffbd59;
    outline: none;
    color: #fff;
    font-weight: 700;
    text-transform: uppercase;
    font-size: 24px;
    border-radius: 30px;
    cursor: pointer;
    box-shadow: 3px 8px 22px rgba(22,21,21,.15);
   transition: background-position .5s;
}
.btn:hover{
    background-position: right;
    color: #1b1b1b;
}
.slider{
    color: #ffbd59;
    margin-left: 14px;
    box-sizing: border-box;
    animation: slider 6s linear infinite;
}
@keyframes slider{
    0%{
        margin-top: -320px;
    }
    5%{
        margin-top: -160px;
    }
    30%{
        margin-top: -160px;
    }
    35%{
        margin-top: 0px;
    }
    65%{
        margin-top: 0px;
    }
    70%{
        margin-top: 160px;
    }
    100%{
        margin-top: 160px;
    }
}

This is the frontend

Without knowing the folder structure and file names we can’t really say much. All I can say is to check the paths and file names of the images.

If you use VS Code it should let you auto-complete the paths. So you can delete the path and start typing it in again and let it find the folder/file for you. If you Ctrl + Click the src image path it should also take you to the folder with the image (if the path is correct).