Bootstrap thumbnail images ignore centering css - html

Question

I cannot center my bootstrap thumbnail images no matter what I try on tablet size and smaller. Once thumbnails reach thoses sizes they no longer scroll to stay center of screen. I have tried everything I can think of from adding center block to both my thumbnail class's and my img responsive class's HTML to text-algin center and margin auto 0. Nothing changes.
Here is my html
<div class="portfolio">
<div class="container">
<a name="porty"></a>
<h1 class="text-center" id = "port">My Work</h1>
<div class="row">
<div class="col-md-4">
<div class="thumbnail ">
<div class="caption">
<h4 class="text-center">A Berine Sanders Tribute page made with HTML,CSS, and Bootstrap</h4> <i class="fa fa-codepen fa-5x fa-fw" id="first"></i>
</div>
<img src="http://goodedevelopment.com/images/Bernie.PNG" class="img-responsive center-block" alt="tribute">
</div>
<legend>Tribute page</legend>
</div>
<div class="col-md-4">
<div class="thumbnail">
<div class="caption">
<h4 class="text-center">Google mockup page made with HTML,CSS,and Bootstrap</h4>
<i class="fa fa-codepen fa-5x fa-fw" id ="second"></i>
</div>
<img src="http://goodedevelopment.com/images/google.png" class="img-resposive center-block" alt="google">
</div>
<legend>Google homepage</legend>
</div>
<div class="col-md-4">
<div class="thumbnail">
<div class="caption">
<h4 class="text-center">A cannon game made with HTML,CSS, and Javascript</h4>
<i class="fa fa-codepen fa-5x fa-fw" id ="icon"></i>
</div>
<img src="http://goodedevelopment.com/images/cannon.png" class="img-responsive center-block" alt="cannon">
</div>
<legend>Cannon game</legend>
</div>
</div>
Here is my CSS
/*Portfolio*/
.portfolio {
background-color:#706C61;
padding-top: 50px;
padding-bottom: 100px;
display: inline-block;
width: 100%;
height: 800px;
position:relative;
}
.portfolio h1 {
font-size: 65px;
font-family: "Roboto",serif !important;
color: #0d0d0d !important;
}
.row {
padding-top: 100px;
}
.thumbnail {
height: 250px;
display: flex;
justify-content: center;
align-items: center;
position: relative;
overflow: hidden;
border: 1px solid black !important;
border-radius: 5px !important;
}
.caption img {
flex-shrink: 0;
max-width 100%;
max-height: 100%;
}
.caption {
position: absolute;
top: 0;
right: 0;
background: rgba(128, 128, 128, 0.75);
width: 100%;
height: 100%;
padding: 2%;
display: none;
text-align: center;
color: #fff !important;
z-index: 2;
font-family: "Montserrat",serif !important;
}
.caption a {
text-decoration: none;
color: white;
}
.caption h4 {
position: relative;
left: 5px;
bottom: 10px;
font-size: 25px;
}
.caption i:hover {
color: orange !important;
}
legend {
font-family: "Roboto",serif !important;
border-bottom: none !important;
color: #0d0d0d !important;
font-size:22px; !important;
height:200px;
}
#first {
position: relative !important;
bottom: -35px !important;
}
#second {
position: relative !important;
bottom: -35px !important;
}
#icon {
position: relative;
top: 30px;
}
#media screen and (min-width:767px) and (max-width:1199px) {
#first {
position: relative;
bottom: 20px;
}
#icon {
top: 50px !important;
}
.caption h4 {
font-size: 20px;
}
}
#media screen and (min-width:767px) and (max-width:991px) {
#first {
position: relative;
top: 50px;
}
.caption h4 {
font-size: 30px;
}
.caption {
font-size: 15px;
}
.caption i {
position: relative;
top: 50px;
}
#icon {
position: relative;
top: 65px !important;
}
.caption .fa {
font-size: 50px;
}
}
#media screen and (max-width: 1200px) {
.portfolio h1 {
font-size: 55px;
}
}
#media screen and (max-width: 991px){
.thumbnail {
height: 369px;
width: 440px;
position: relative;
right: -142px;
bottom: 48px;
}
.portfolio{
height: 2650px;
}
#profile li {
position: relative;
left: 60px;
}
.caption h4 {
font-size: px !important;
}
.caption .fa {
font-size: 80px !important;
}
legend {
height: 80px;
position: relative;
left: 139px;
bottom: 53px;
}
}
#media screen and (max-width: 965px) {
.portfolio {
margin-top: -150px !important;
}
}
#media screen and (max-width:767px) {
#first {
position: relative;
top: 25px;
}
.caption h4 {
font-size: 30px;
}
.caption {
font-size: 15px;
}
#port{
width: 50%;
height: 50%;
overflow: auto;
margin: auto;
position: absolute;
top: -1285px;
left: 0;
bottom: 0;
right: 0;
}
.thumbnail {
position: relative;
bottom: 0px;
}
legend
{
position: relative;
bottom: 13px;
}
}
#media screen and (max-width: 454px){
.caption h4{
font-size:25px;
}
#first{
top:15px;
}
#second{
top:15px;
}
}
#media screen and (max-width:400px) {
#icon {
position: relative;
bottom: 20px;
}
}
#media screen and (max-width:397px) {
#icon {
position: relative;
top: 0px;
}
}
#media screen and (max-width:390px) {
#first{
top:5px;
}
}
#media screen and (max-width:325px) {
.caption .fa {
font-size:60px;
}
}
#media screen and (max-width:307px) {
#first{
top:-5px;
}
}
/*End Portfolio*/
Here is the website
And finally here is a screenshot of what I am experiencing any help would be greatly appreciated thanks!

Answer 1

Instead of just using class="col-md-4" you should include "instructions" for Bootstrap at different screen sizes. Using multiple classes like class="col-xs-12 col-sm-6 col-md-4" would adjust the number of columns at the various screen sizes, making it easy to center the contents of each column, and just use the "img-responsive" class on the images so they will always fit in the column they are in. Then when the screen size is smaller, fewer columns will be displayed but the content of the column remains the same and stays centered in the column. If you want to center the column on the screen without filling the width of the screen (like to use col-xs-10 so it doesn't fill the width of 12 col's) then use the col-x-offset-x class to create a "blank" column to the left of where your div will display. You can use combinations of screen sizes and offsets as needed. The grid makes it really easy to get the alignment you want at different sizes without having to use CSS to define exact pixels for margins and whatnot. Once you start overwriting the CSS with "other instructions" as far as height/width go, things can get goofy...

Answer 2

Your fixed-navbar are with a width bigger than lower resolutions, theres alot of blank space on the right when you drop the resolution. I recommend you start developing your website following this basic bootstrap responsible template.
<!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" />
<meta name="description" content="" />
<meta name="author" content="" />
<title>Bare - Start Bootstrap Template</title>
<!-- Custom CSS -->
<link data-require="bootstrap-css#3.2.0" data-semver="3.2.0" rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css" />
<script data-require="jquery#*" data-semver="3.0.0" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.0.0/jquery.js"></script>
<style>
body {
padding-top: 70px;
/* Required padding for .navbar-fixed-top. Remove if using .navbar-static-top. Change if height of navigation changes. */
}
</style>
<!-- HTML5 Shim and Respond.js IE8 support of HTML5 elements and media queries -->
<!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
<!--[if lt IE 9]>
<script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js"></script>
<script src="https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js"></script>
<![endif]-->
</head>
<body>
<!-- Navigation -->
<nav class="navbar navbar-inverse navbar-fixed-top" role="navigation">
<div class="container">
<!-- Brand and toggle get grouped for better mobile display -->
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">Start Bootstrap</a>
</div>
<!-- Collect the nav links, forms, and other content for toggling -->
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
<ul class="nav navbar-nav">
<li>
About
</li>
<li>
Services
</li>
<li>
Contact
</li>
</ul>
</div>
<!-- /.navbar-collapse -->
</div>
<!-- /.container -->
</nav>
<!-- Page Content -->
<div class="container">
<div class="row">
<div class="col-lg-12 text-center">
<h1>A Bootstrap Starter Template</h1>
<p class="lead">Complete with pre-defined file paths that you won't have to change!!</p>
<ul class="list-unstyled">
<li>Bootstrap v3.3.7</li>
<li>jQuery v1.11.1</li>
</ul>
</div>
</div>
<!-- /.row -->
</div>
<!-- /.container -->
</body>
</html>
Rebase your website inside the .container and link your style and keep going.. I hope it helps you to understand better the concepts of bootstrap, i cannot do the whole job for you after all you are a full stack developer.