decor-6-site/site/snippets/blocks/spreadimage.php

<?php

/** @var \Kirby\Cms\Block $block */
$alt     = $block->alt();
$caption = $block->caption();
$src     = null;
$fullWidth	 = $block->fullwidth()->toBool();

if ($block->location() == 'web') {
    $src = $block->src()->esc();
} elseif ($image = $block->image()->toFile()) {
    $alt = $alt->or($image->alt());
    $src = $image->url();
}

$GLOBALS['figCount'] = ($GLOBALS['figCount'] ?? 0) + 1;
$figId = 'fig-' . Str::slug($block->parent()?->author() ?? '') . '-' . $GLOBALS['figCount'];

?>

<?php if ($src): ?>
	<div class="spread-image">
		<figure id="<?= $figId ?>" class="<?= $fullWidth ? 'full-width' : '' ?>">
			<img src="<?= $src ?>" alt="<?= $alt->esc() ?>">
			<?php if ($caption->isNotEmpty()): ?>
			  <figcaption><?= $caption ?></figcaption>
		  <?php endif ?>
		</figure>
	</div>
<?php endif ?>