Hi.
If you’re using bootstrap I think adding “max-width” property to your CSS might do the trick with images.
If you want to add a menu button for smaller devices, I advice to read about media queries first. My trick is to add a menu icon to the right of your navbar and give it class with “display: none”. Then, using media query you can change the display of the icon and also hide (also with display property) your normal menu.
I used jquery to create a list menu on icon click in my portfolio, but there is a trick with :target so you can make it just with CSS.