've been taking a web dev course on Udemy. In the course they teach you how to use Bootstrap. You dont need to fully understand what that is but it makes designing responsive web pages that stay neat when you re-size the screen very easy to create.
I used what I learned and created an image gallery with images of my son. None of the links at the top function they are just there for show.
https://codepen.io/FrontN_Dev/full/wedWGm
Not sure how the page opens for you guys but to see the page in full view just click onto the button in the top right, "Change View" and click onto "Full page". If you open this link on your phone it should load in a mobile format.
If you want to see how it responds when you go to a tablet or mobile screen size you can manually change your browser screen size or if you use Chrome just hit F12 on your keyboard.
The images go from 3 in a row to 1 in a row and then the menu becomes a drop down.