I do believe I have never seen an Icon of the Theotokos without the Child. The older depictions of the Theotokos usually have her with the Christ-Child, but for the ones of the Annunciation (and then the Child is implied), in both East and West. The more traditional depictions of the Theotokos in East and West say something very important: we venerate this Woman because of the Child in her arms (or womb as the case sometimes is). Thus, with that artistically-given focus, veneration of the Theotokos can never be separated, conceptually or practically, from the worship of the Christ. The word Theotokos, God-Bearer, has the same effect in text and prayers.
The only images I have seen of Mary which do not include her Son have been Western works inspired by the “apparitions” seen through the last five or so centuries. I am not saying others do not exist, but I simply have not been able to find one that is not traced back to some “apparition.”
The missing sandal, I do think is a reference to Lk xxx, 16.