You can target AOL Mail by using the CSS selector class .aolmail_ and adding your styles.
AOL Mail HTML codes
By default AOL uses it’s own font styling. The fix is very simple and can be overwritten using your own embedded CSS.
Some email clients and webmail services such as AOL Mail, Gmail, Lotus, Outlook, Thunderbird, and Windows Mail will display a blue or black border around images that are linked but don’t have a border specified.