28 year old, sagging breasts. Currently size 12E. What do you recommend? (Photo)

Hello and thank you for your questions and pictures.  Judging from your photographs you will likely need both a breast lift with an implant.  The implant will give you the upper pole fullness you are looking for and the breast lift will correct the loose breast and skin to give you a more shapely and lifted breast.  Good Luck

Based on these photographs you need a breast lift.  The fullness will come from an augmentation.  It is often best to stage these operations.

Thank you for the question and pictures. Congratulations on your significant weight loss!   Based on your stated goals, I think that you will benefit from  breast augmentation/lifting surgery. In my practice, I would do the procedures in 2 stages; the breast lift initially followed by the breast augmentation procedure several months subsequently.  My recommendations are based on safety considerations, avoidance of complications,  and  improving the odds that your goals will be achieved in the long-term.  
You will find, as you do your due diligence ( which you should do carefully), that you will receive many different opinions.   Ultimately, it will be important for you to select your plastic surgeon carefully and communicate your goals carefully as well. In my practice, the use of goal pictures and computer imaging will be helpful in communication of goals and determining the best  surgical plan to help achieve your goals. Some general thoughts regarding breast augmentation/lifting surgery may be helpful to you as you learn more.
Breast augmentation/lifting surgery is more complicated than either one of the procedures done separately. On the one hand, breast augmentation surgery is expanding the breast skin “envelope” while breast lifting is (by definition) tightening up the breast skin envelope. These 2 forces are counteracting each other. Therefore, it becomes important to remove the appropriate amount of breast skin and to use the appropriate  size/profile of breast implants to balance these 2 forces appropriately and to allow for achievement of the patient's goals while minimizing risks of complications.  Again, despite these efforts, breast implant and/or tissue/skin complications may arise causing minor or significant complications.
 Generally speaking, it is difficult to achieve the “perfect” result with breast augmentation/lifting surgery, despite best efforts.  Patients should be aware of the complexity of this combination procedure, achieve REALISTIC EXPECTATIONS prior to proceeding, and understand that additional surgery ( along with the additional recovery time, stress, expenses etc) may be necessary in the short or long-term. Patients should understand that the results of the procedure will not necessarily match aesthetically the results of patients who have undergone breast augmentation surgery only.
For example, some patients who wish to maintain long-term superior pole volume/"roundness" may find that this result is not achieved after the initial breast augmentation/lifting operation.  An additional operation, possibly involving capsulorrhaphy, may be necessary to achieve the patient's longer-term goals ( with superior pole volume/roundness).  It is helpful if patients understand that this breast implant capsule used to provide the support for the breast implant is not present during the initial breast augmentation/lifting operation.  The capsule (layer of scar tissue) forms around the breast implant and may be a good source of supportive tissue during revisionary breast surgery,  Including correction of breast implant displacement/malposition problems ( such as bottoming out, symmastia,  lateral displacement etc).
 Potential risks associated with breast augmentation/lifting surgery include infection, bleeding, incision line healing problems, loss/change of nipple/areola complex sensation, and blood flow related issues  to causing skin or tissue necrosis.   Poor scarring,  pigment changes, areola/nipple asymmetry etc. are also potential problems. Again, patients may experience implant related problems such as encapsulation, leakage, displacement problems ( too high, bottoming out, lateral displacement, asymmetric positioning etc.), rippling/palpability of breast implants etc.  Patients may also be dissatisfied with breast size, shape, and/or how the  breast implants and overlying breast tissues “interface” with one another.    Occasionally, a breast implant may even have to be removed and the patient will generally be “implant free” for several months at least.  Obviously, this situation can be quite physically, emotionally, and psychosocially stressful to the patient involved.
Given the complexity  of the combination breast augmentation/lifting operation and the greater risk of revisionary breast surgery needed, there are good plastic surgeons who will insist on doing the procedures separately.
For me, if I see a patient who needs a great degree of lifting, who has lost a lot of skin elasticity, or  whose goal is a very large augmentation then I think it is best to do the procedures in 2 stages (in order to avoid serious complications). However, doing the procedure in one stage does increase the risks of complications in general and the potential need for further surgery. This increased risk must be weighed against the practical benefits of a single stage procedure (which most patients would prefer).

Conversely, if I see a patient who requires minimal to moderate lifting along with a small to moderate size augmentation (and has good skin quality), then doing the procedure one stage is much safer. Nevertheless, the potential risks  are greater with a 1 stage  procedure and the patient does have a higher  likelihood of needing revisionary surgery.
Having discussed some of the downsides  and potential risks/complications associated with breast augmentation/lifting surgery, most patients (If properly selected and who are doing the operations at the right time of their lives  psychosocially) accept the scars associated with breast augmentation/breast lifting surgery as long as they are happy with the improvement in contour, size, and symmetry.
 I hope that this summary of SOME  of the issues surrounding breast augmentation/lifting surgery  is helpful to you and other women considering this procedure in the future.  Also, given her young age, I would suggest that you TIME  the procedures carefully in relation to your life circumstances ( such as relationships, pregnancies…).
 Obviously, much to consider… The attached link may also be helpful.
 Best wishes.