Translation missing in lightbox for “fbx-count”

When you click on an image and it opens in lightbox, the caption is a counter of the images like “image 1 of 24” but i have the website in spanish and that doesnt change, always in english.

I search by loco translate and couldn’t find anywhere to change it. Where can i do it?

Thanks.

Screenshot: https://i.imgur.com/bTO48Ur.png