Adding an image as sass variable to an html-twig file - html

Question

This is a question, partially related to a previous discussion: Have a variable in images path in Sass?
I'm attempting to pass a logo image and apply an specific style to this logo through one of my labels on a twig file (quite similar to HTML) on a Symfony Project.
I fixed it with the background image, which actually is working, but the logo still doesn't appear anywhere... Could you help me with that?
Despite the background image is actually working, it gives me a warning...
`/* variables.scss file */
$footer-icon : url('image/'+ $customer +'/icon/footer-icon.svg');
$background-image : url('image/'+ $customer +'/'+'background.jpg');
/*****************/
/*_frontend-utils.scss*/
.beforeBackgroundImage {
overflow-x: hidden;
}
.backgroundImage {
background-image: $background-image;
}
.afterBackgroundImage {
background-position-y: bottom;
background-position-x: center;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
background-repeat: no-repeat;
height: 100%;
}
/*****************/
/* frontend.html.twig */
<div id="wrap" class="beforeBackgroundImage backgroundImage afterBackgroundImage">
/*it works! =)*/
/*****************/
/*_footer.scss*/
.footerSecond {
display: block;
bottom: 0;
position: absolute;
height: 50px;
text-align: center;
width: 100%;
left: 0
}
.beforeFooterImage {
margin: 0px;
height: 48px;
}
/*I also tried with background-image...*/
.footerImage {
image: $footer-icon;
}
/*****************/
/*footer.html.twig*/
<div class="pull-left"class="opacityOne beforeFooterImage footerImage">
`
I could fix it by directly writing the image path inside the label, but I'd like to separate this from the code
<div class="pull-left"class="opacityOne">
<img class="beforeFooterImage" src="{{asset('bundles/app/img/footer-icon.svg')}}" alt="" />
Thanks in advance