Hey, nico13100 thanks for informing your issue. You can add a space between the product image by adding some code to your theme functions.php. you can change the offset top value as your need.
function ai1wsa_offset_top(){
?>
<script>
jQuery(document).ready(function () {
jQuery('.woocommerce-product-gallery').stickr({
offsetTop: 30,
});
});
</script>
<?php
}
add_action( 'wp_footer', 'ai1wsa_offset_top' );
Unable the sticky position on mobiles issue will be fixed on my free time & release its next version.