I loaded in multiple images on my website from the internet. Is it possible to give all those images an hexagon shape in a responsive grid?
you can use vertical-padding in % + pseudo element to draw a square to begin with.
Then , use a second element to draw a mask.
DEMO

HTML
CSS
.hex {
position:relative;
margin:auto;
text-align:center;
overflow:hidden;
white-space:nowrap;
display:table;
}
.hex:before {
content:'';
padding-top:120%;
display:inline-block;
vertical-align:middle;
}
.hex:after {
content:'';
position:absolute;
top:0%;
left:-10%;
width:120%;
padding-top:120%;
transform: rotatex(45deg) rotate(45deg);
text-align:center;
box-shadow:0 0 0 200px white;;
}
.hex img {
display:inline-block;
vertical-align:middle;
margin:0 -10px;
}