Just copy something like this into your CSS file twice, rename one like so
Code:
.image {
margin-top: 1em;
margin-bottom: 1em;
margin-left: 1.2em;
text-align: center;
}
.image100 {
margin-top: 1em;
margin-bottom: 1em;
margin-left: 1.2em;
text-align: center;
max-width: 100%
}