Well, first of all, it would be the larva that would be a leaf miner, not the adult. The adults feed on flower nectar and sometimes take up water from incidental sources such as the surface of your potato leaf, which probably is what this moth was doing when you photographed it.

Also note that, although Family Gracillariidae is known by the common name of leafminer moths, there are many other families of micro-moths, in addition to Gracillariidae, in which the larvae of some or all species are leaf miners.

One such family is Heliozelidae, and this is the family to which your moth belongs. Your moth is a member of the heliozelid genus Antispila. Of the several Antispila species that occur in the eastern USA, your moth most closely resembles Antispila cornifoliella, the larva of which is a leaf miner on dogwood.

For more information on Heliozelidae, see http://microleps.org/Guide/Heliozelidae/index.html (and click on the link for Antispila, for more info on a few of our species in that genus).