Also managed to solve this reading trough this topic, thank you all! My solution may work for others so also posting it here:
In my “block.json”:
{
"name": "acf/my-acf-block",
"title": "My ACF Block",
"description": "Description of this block.",
"style": "file:./my-acf-block.css",
"category": "my-custom-category",
"icon": "random-icon-or-svg",
"textdomain": "my-textdomain",
"acf": {
"mode": "edit",
"renderTemplate": "my-acf-block.php"
},
"supports": {
"align": [
"full"
]
},
"example": {
"attributes": {
"mode": "preview",
"data": {
"preview_image_my_acf_block": "assets/img/my-placeholder.jpg"
}
}
}
}
And in “my-acf-block.php” I start with:
<?php
if( isset( $block['data']['preview_image_my_acf_block'] ) ) {
echo '<img src="' . CONSTANT_THEME_URL . $block['data']['preview_image_my_acf_block'] . ' " style="width: 100%; height: auto;">';
return;
}
// the rest of my template render..
?>
The “CONSTANT_THEME_URL” is a constant that I normally define within my theme and returns the URL of the current theme, but including trailingslashit().
