I sent some pictures from "Pictures" to "Documents". I am trying to send the pictures from "Documents" back to "Pictures" but I don't know how. How do I do this?

You have only sent a copy to documents. If check, you will find the same picture(s) file in both locations. You can safely delete the documents copy after confirming that it is still in My Pictures. Changing the "send to" menu is not recommended. The picture folder is not availble by default as a "send to" location.