Toufiq,
I've done spending lot of time to do what you said to me (pairing dimension and weight of all images), without any results.
So I've done a rollback to the previous situation that is good to me.
I need to resolve this issue, I've spent money again to have assistance from you.
Sp Portfolio works fine in any case on PC browsers, and in some cases on tablets and cell phones but there is a way in which SP Portfolio works fine: try to follow these steps:
1 - Clear the cache of your browser on cell phone
2 - Go there:
https://www.consulenzapizzerie.it/
3 - Click on "I Nostri Lavori": you'll see compressed items on the half end of the list
4 - Now, click on any tags that is not "Show All": you'll see that list works fine
5 - Now, click on "Show All" tag: you'll see that the list is perfect and works as it has to be.
This sequence show that it is not a problem that lets you to said me the is my issue but that it is sure that is an issue generating by your developer.
Please, try the sequence. If I was wrong in the implementation of SP Portfolio, it doesn't work in any case, and I'sure that you agree with that.
Hope you'll find the solution.