Check out example codes for "how to frame a picture with color css". It will help you in understanding the concepts better.

Code Example 1

/* Simple thin border */
img { 
   border:1px solid #021a40;
}

/* Double Border */
img {
   padding:1px;
   border:1px solid #021a40;
}

/* Double Border with different inside border color*/
img {
   padding:1px;
   border:1px solid #021a40;
   background-color:#ff0;
}

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