What an interesting concept. I had never heard of this before. For some reason, Mary's fully exposed breast, nipple in detail, with Jesus going toward it doesn't strike me as the material of an icon.
Ironically,
this [
fisheaters.com] page discussing this devotion lauds "discreet" breastfeeding while linking to images of the Virgin Mary uncovered and unclothed with her breast hanging out of her garment, such as
this [
fisheaters.com] (Rembrandt, A.D. 1630s),
this [
fisheaters.com] (El Greco, ca. A.D. 1600),
this [
fisheaters.com] (Gerard David, ca. A.D. 1490), and
this [
fisheaters.com] (Adriaen van der Werf, 1714).