We can create a data-info attribute, which can receive a space-separated list of anything we need to make note of. In this case, we'll make note of external links and links to images -- just for the example.
With that markup in place, now we can target any tags that have either of those values, by using the ~ attributes selector trick.
<a href="path/to/image.jpg" data-info="external image"> Click Me, Fool </a>
/* Target data-info attr that contains the value "external" */
a[data-info~="external"] {
color: red;
}
/* And which contain the value "image" */
a[data-info~="image"] {
border: 1px solid black;
}