How can I add borders to all my images?

Hi Guys,

I would like to add borders around all my images. I know in some themes it is automatic.

A previous thread said you can insert:

“.entry-content img {
border: 1px solid #ccc;
}”

but i’m not exactly sure where to put it.

is this suppose to go here:

” /*————————————————————–
11.0 Media
————————————————————–*/
img {
max-width: 100%;
height: auto;
}
.page-content img.wp-smiley,
.entry-content img.wp-smiley
.comment-content img.wp-smiley {
border: none;
margin-bottom: 0;
margin-top: 0;
padding: 0;
}”

Many thanks
sam