Solution to set background-image using [shortcode]? - php

Question

I'd like to set a random background-image into a <div>Container</div>
To keep it simple I installed a plugin using [shortcode] to display random images. This works fine.
How to get the shortcode [wp-image-refresh] working together with background-image:url(...)
I tried it even as inline-style with no result.
This is what I have:
HTML
<div class="header_random-image">
<div id="hero"></div>
</div>
CSS
#hero {
background-image: url('<?php echo do_shortcode("[wp-image-refresh]"); ?>');
background-size: cover;
background-position: 50% 30%;
height:70vh;
width: 100%;
margin-top: -65px;
}
Another try with no result: Inline-style
<div class="header_random-image">
<div style="background-image: url('<?php echo do_shortcode("[wp-image-refresh]"); ?>')"></div>
</div>
Could anybody be so kind to help? Or does anybody has a simple solution to place div-random-background-images?
Best from Berlin

Answer 1

In most cases your CSS code will be served in a static file, thus the php code won't execute.
As the inline example doesn't work either, I guess the short code does not return an image url but a full image tag instead. The plugin's description
confirms this assumption. WP-IMAGE-REFRESH
You could try this:
PHP
<div class="header_random-image">
<?php echo do_shortcode("[wp-image-refresh class='hero_class']"); ?>
</div>
CSS
.header_random-image {
overflow: hidden;
}
.hero_class {
height: 100%;
width: auto;
margin-top: 0;
}
This should display the image. You'd still have to center it if you want (use flex-box) and check for problems caused on different screen sizes depending on the side ratio of your uploaded images and solve them with some Javascript.
Alternative
Use ACF Pro and add a gallery field to your posts/pages or an option page if you want the same images on all views.
PHP
<?php
$images = get_field('name-of-your-gallery-field');
shuffle($images);
$imageUrl = images[0]['url'];
<div class="header_random-image">
<div style="background-image: url('<?= $imageUrl ?>"); ?>')"></div>
</div>