Horizontal scroll css?

Just set your width to auto:

#myWorkContent{
    width: auto;
    height:210px;
    border: 13px solid #bed5cd;
    overflow-x: scroll;
    overflow-y: hidden;
    white-space: nowrap;
}

This way your div can be as wide as possible, so you can add as many kitty images as possible ;3

Your div’s width will expand based on the child elements it contains.

jsFiddle