Highlight Image - Click On Another Row The First Border That Changed Obviously Changes Back

I have say 12 pics on a page, in 3 rows of 4. The rows of pics are there so that a choice can be made from each row and I'm using a function <script>

var highlight_color = '#FF0033'; function toggle_highlight(id) { var images = document.getElementsByTagName('img'); for (var i = 0; i < images.length; i++) { var image = images[i]; image.style.borderColor = image.id == id ? highlight_color : 'white'; } } </script>

to toggle a border colour change so that you can see what was chosen from each row. The function I have used is fine in that it works, but I can only choose one picture and have the border changed, then if I click on another row the first border that changed obviously changes back and the new selection is highlighted. I don't really know where to go from here.