Icon list icons not displaying

I have used the Icon list element in our website and when I display the page, I can see the icons are there (screenshot), but they are small and transparent (can barely see them). If I change the size of the browser window or change the zoom level (text size) of the browser window, the icons will appear (screenshot)

I’ve tried displaying the page in IE, Chrome and Firefox and all browsers display it the same way. The only way the icons will display is if I change the size of the browser window or change the zoom setting.

I’ve tried deactivating my plugins and it still displays the same way.

Is there a trick to getting the icons to display without resizing the browser window? Please advise on how to fix this behavior. Thanks