Saline implants under the muscle for a small frame? (Photo)

Saline and silicone gel implants both can have great results. Saline does have more rippling which may show more in a thin person. Going under the muscle will help. The size is the most important factor and that is something to discuss at the time of your consultation. As long as the implant is proportionate to your body, the skin will not be overstretched.

Thank you for the question and picture. Your breasts do demonstrate some of the qualities seen with tuberous (constricted) breasts; there is a wide range when it comes to tuberous/constricted breast presentation.
Generally speaking, some of the characteristics seen with tuberous breasts include a very narrow base, short distance from areola to inframammary fold, tight (constricted) lower pole of the breasts, relatively wide space between the breasts, "puffy” areola and some degree of ptosis (drooping).
Generally, correction of tuberous breast anomalies involves breast augmentation with areola reduction / mastopexy procedure. The distance from the inframammary fold is increased (to create a more rounded out appearance). Proper implant positioning improves the distance (cleavage) between the breasts. The areola reduction helps to treat the pointed and "puffy" appearance of the areola.Patients should be aware that the final result will take months to see and that they will need to be patient and that revisionary surgery is more likely than in patients who do not present with tuberous (constricted) breasts.
In your case, if the appearance/shape/size of the breasts are a concern, you may be an excellent candidate for corrective surgery.
When you are ready, please make sure you consult with well experienced board-certified plastic surgeons who have significant (demonstrable) experience with this type of surgery. Although I have utilized both saline and silicone gel breast implants for patients in your situation, you made the best off with the use of silicone gel breast implants ( given the paucity of soft tissue coverage along the lower breast poles seen with patients with constricted breasts).
I hope this, and the attached link (dedicated to corrective surgery for patients with tuberous/constricted breasts) helps. Best wishes.