Size of butt implants? (Photo)

 Please keep in mind that a physical exam is always first necessary before providing any final surgical recommendations. Based upon your photos, a Stanton Anatomic shape buttock implant may serve you best.  Please read on:
 Make no mistake, it is indisputable that the best position (aka "placement") for buttock implants  is in the intramuscular plane not on top of the muscle and not "sub-fascial" which is exactly the same as on top of the muscle - so please do not be fooled by this terminology. One of the most important factors in creating the perfect derriere with implants is indeed selecting the right size AND shape. I have found the best way to assure this is to simply measure the actual dimensions of the patient’s buttock cheeks.  By the way, I commend you on your measuring efforts however you have not done it quite accurately.  With these anatomical measurements, I can select an implant that not only significantly augments the buttock but also supplies the correct 3-dimensional enhancement to look as real as possible...even in the most petite patients. Traditionally, teardrop oval implants have a 30+% risk of rotation and thus unnaturally change the buttock shape/appearance when doing so.  However, one and a half years ago I created and patented a new "Stanton Anatomic" shaped implant that avoids this issue AND provides as much projection as similar volume (cc's) round implants - I have not had a single rotation problem in 250+ patients. Additionally Stanton Anatomic buttock implants tend to maintain a more natural buttock shape/curve even when bending over - an otherwise not uncommon problem with round implants. This is a huge benefit by the fact that ~90+% of  patients have more of an oval shaped buttock cheek than round, thus creating a much more natural and harmonious buttock contour for the majority of patients. Finally, buttock implants, including Stanton Anatomics, do indeed significantly augment the hips especially by filling in much of the "hip dip". So in summary, the only way for you to know what implant works best is to consult with a board certified plastic surgeon specializing in this procedure and have him/her take your measurements before selecting an implant and proceeding with surgery. Also not a bad idea to select the surgeon who has the most experience, the best reviews, and the most pleasing before and after photos.   

It is very difficult to determine the exact size and shape implant you will require to best match your ideal butt image without an examination by a board certified plastic surgeon. Not just any board certified plastic surgeon, but one with many years of frequently performing breast augmentation surgery including different approaches, techniques and implant choices. This is because several measurements not to mention your breast characteristics are needed to determine the optimal implant size to obtain your goals. Without knowing these dimensions it would be difficult to make this determination. For example, the existing base width of your buttock will determine, in many cases, the maximal volume per implant profile that you can accommodate. Liposuction of your lower back and fat transfer is also helpful as an adjunct to implants. Using “want to be” photos however are useful if simply provided to the surgeon.

A butt implant of more than 400 cc is often too big, leading to increase risk of skin thinning, implant protrusion, malposition, and other untoward side effects.  Simply put, the right implant size is determined by your underlying anatomy, particularly relating to your soft tissue coverage and butt dimension.However, have you consider Brazilian butt lift?  Instead of synthetic implants, the technique uses your own fat.  Hence, it requires large volume liposuction to get enough "natural filler," which is then purified and re-injected into your backside.Brazilian butt lift traditionally collects the excess fat from the flanks and lower back (along with other donor sites) to further enhance the shape and projection of the buttocks and hips.Good luck and best wishes.