Why are my nipples different positions, and breasts different shapes and sizes? (Photo)

Based on these photographs it appears that you have a very nice result.  Any subtle asymmetry that you have is not significant and is natural.

The photos make it difficult to assess for symmetry. It is also too early in the post operative period to be concerned about asymmetry. Several months will need to pass before you can make a true assessment of the final result. It is important to note that asymmetry of the breasts and the nipple complex are common. A breast augmentation alone will not correct those asymmetries. Often leaving normal minor asymmetries alone will produce a better overall result.

You are still early in the healing process, so be patient.  Overall it looks as if you are making normal, good progress.  The implants need months to settle and they may do so at different rates.  Remember they are sisters, not twins.  It is not uncommon to see one implant settling sooner than the other.  This may account for the differences you are noticing.  Be patient and continue your postoperative instructions from your surgeon.  I think you will be happy with your result!

The photos are not ideal (should be straight on , arms at side for the front view), and I am not seeing much in the way of uneven breasts or nipples/areolas. I do not see any hint of bottoming out. It is quite common for women who, though by six months have nice even results, are not symmetric early in the course of recovery.  The pec muscles are uneven in strength (right v left) and each compresses the implant differently until both have relaxed to accommodate the implants.Patience, follow with your surgeon.  All the best.