Going from subglandular to submuscular -- is it possible? (Photo)

The photo quality makes it difficult to say definitively what would be needed surgically. Generally speaking, yes it is entirely possible to go from a subglandular to submuscular plane. Often times when I perform a pocket switch I will use an absorbable mesh (internal bra) to help support the implant laterally and control the newly created pocket. Any decision about adding a lift with the breast augmentation would depend on a more detailed assessment of your anatomy and whether your goal is to keep similarly sized implants.
Sean Fisher Aesthetic Plastic Surgeon

A full frontal view with you standing would have been very helpful. However, you can get good improvement placing the implants behind the muscle for better coverage. I do not recommend going larger.