last miniature not visible

hi, in all the galleries I created the last miniature is not visible. The image in the large slideshow is displayed but the corresponding thumbnail is displayed.

For example on this page bit.ly/2kXE2P6 there are 4 photos but there are 3 thumbnails.

But if I in the following code set width 400px (for example) thumbnail is visible.

how can I set this value (and above all from which class is controlled) so that it is compatible with the responsive system?
Thank you

Hi
actually I don't see any slideshow in your page, it seems that you have a JS problem
can you check
CEd

Thank you so much for the answer above all. By opening the page in my console I do not see any mistakes or Js conflicts. In my template there is also the file that calls the no conflict, I also provided yesterday to install the Easy Jquery plugin. Can you visit the link of the previous post again?

I have checked again and now the slideshow is showing, but by my side I see the 4 thumbs according to the 4 images loaded
do you still have the same problem on your side ?
try to clear your browser cache

Yes, I see 3 instead of 4 (tried with different browsers and different PCs.) If I change this value via the console:

and I put, for example, width: 300px to display correctly 4. How can I intervene on the admin side (or code side) to increase the width?

Ps. in the configuration I set miniature width to 55 so in reality the value 242 should contain all 4.

sorry but actually I have tested with 2 pcs and Firefox + Chrome browsers and I see 4 thumbs.
your issue could be related to a CSS conflict, for example if there is some padding/margin applied to the thumbs from the template css, it could give a wrong calculation ... this is just an idea as I can not see it