Boostrap css put image as overlay in header - css

Question

I am trying to put a image inside a header in a boostrap card, I do know there are other questions like this but I seriously tried everything.
Here is the code:
<div class="container">
<div style="padding: 20px 0px;" *ngFor="let blog of blogs">
<div class="card">
<div class="card-header" (click)="navigate('Blog')">
<a (click)="navigate(blog.title)">{{ blog.title }}</a>
</div>
<div class="card-body">
<p class="card-text">
{{ blog.summary }}
</p>
</div>
</div>
</div>
</div>
css:
.card-header {
background: rgba(0, 255, 0, 0.61);
color: rgb(0, 0, 0);
font-weight: bold;
cursor: pointer;
}
.card-body {
background: #43484d;
}
.card-text {
color: #6cffce;
font-weight: bold;
}
I have tried
background-image: url(imagepath)
it does not work
I also tried
<image src ...>
as top-overlay but that neither
I just want to put an image in the header which will be transparent with on the top a color (kind of like looking into a glass type of thing)

Answer 1

not exactly sure what you want. check this snippet if it gives you any ideas.
.card-header {
background: linear-gradient(rgba(255, 0, 0, 0.25), rgba(255, 0, 0, 0.25)), url(http://www.tedgoas.com/assets/images/work/stack-overflow/cover.jpg) no-repeat center center;
height: 200px;
position: relative;
}
.card-header a {
color: white;
font-weight: bold;
font-size: 50px;
position: absolute;
top: 40%;
left: 40%;
}
.card-body {
background: #43484d;
}
.card-text {
color: #6cffce;
font-weight: bold;
}
<div class="container">
<div>
<div class="card">
<div class="card-header">
<a>Header</a>
</div>
<div class="card-body">
<p class="card-text">
Body
</p>
</div>
</div>
</div>
</div>

Answer 2

Here is your code as per your requirement see the code card-header same thing you can apply in anywhere it will work fine. here is link codepen link here
<div class="container">
<div style="padding: 20px 0px;" *ngFor="let blog of blogs">
<div class="card">
<div class="card-header" (click)="navigate('Blog')">
<a (click)="navigate(blog.title)">link</a>
</div>
<div class="card-body">
<p class="card-text">
Para1
</p>
</div>
</div>
</div>
</div>
Css goes here...
html, body {
height: 100%;
width: 100%;
margin: 0;
color: #f9f0f3;
background: #D21237;
}
.card-header {
background: rgba(0, 255, 0, 0.61);
color: rgb(0, 0, 0);
font-weight: bold;
cursor: pointer;
position:relative;
height:10vh;
}
.card-header::before{
content:"";
background-image: url("http://www.hdnicewallpapers.com/Walls/Big/Abstract/Red_and_Blue_Smoke_Creative_Design_Wallpaper.jpg");
height:10vh;
position: absolute;
top:0px;
width:100%;
z-index:99999;
}
.card-body {
background: #43484d;
}
.card-text {
color: #6cffce;
font-weight: bold;
}