@ariom the image url should not look like yours. They should include only image id, not product id. That means that url https://www.mudrashop.com/7327-home_default/telo-mare-90x165-cm-spugna-jacquard-stelle-marine-home-sweet-home.jpg is correct.
I don't know how you managed to get product id to the image url. Do you have some module or override that do this? Anyway, you are going to have problems with this schema, because most modules (and tb core) expects image id to be single identifier.
Note that you already have some problems on your site. On your homepage, products img elements contains this code
<img class="img-responsive center-block"
srcset="
https://www.mudrashop.com/7900-home_default_smallest/borsina-a-tracolla-in-pelle-intrecciata-aba-368.jpg 211w,
https://www.mudrashop.com/7900-home_default_smaller/borsina-a-tracolla-in-pelle-intrecciata-aba-368.jpg 218w,
https://www.mudrashop.com/4663-7900-home_default/borsina-a-tracolla-in-pelle-intrecciata-aba-368.jpg 250w
"
sizes="(min-width: 1200px) 250px, (min-width: 992px) 218px, (min-width: 768px) 211px, 250px"
alt="BORSINA A TRACOLLA IN PELLE INTRECCIATA ABA 368" title="BORSINA A TRACOLLA IN PELLE INTRECCIATA ABA 368"
itemprop="image"
width="250"
height="250">
As you can see, srcsset attributes references 3 versions of the image with id 7900, but only one of them contains product id (and is accessible).
I suggest you to investigate this problem right away.
Edit: it looks like this is caused by enabled PS_LEGACY_IMAGES option. You could try these steps
1) move legacy images:
2) disable Legacy Images option
3) regenerate images
4) regenerate .htaccess