The implants will drop some into the breast over the course of a year but I would have recommended a lift to center the nipple/areola on the implant. You can still get a lift later if you are unhappy with your final result. You could place a larger implant at that time or do some fat grafting to increase the volume.
there is a rule in plastic surgery that says: implants alone do not correct mammary ptosis, according to your pictures your breasts are dropped before and after the surgery, the only difference is the volumen. In these cases it is important to discuss posibilities of a mastopexy with your plastic surgeon.
It is always good to discuss a lift especially in your case. Many times we can get the nipple complex elevated enough the size of implnat and the technique used at placement. In this instance a skin lift would help you.
Yes you need a lifting operation. Do you know the cm distance pre op from your sternal notch to the nipples?? Bet it was over 26 cm.. Thus a lift was indicated..