4 years post butt implants, but starting to sag. Can my butt be lifted? (photos)

Allow me to answer your question as best i can based upon your photos. However, please keep in mind that an in-person consultation with physical exam is first necessary before any legitimate evaluation or final surgical recommendations can be made.  That being said, you may achieve what you are looking for by revision of the buttock implants themselves. It’s possible that the sagging is occurring because they are too superficial and creating a deeper pocket within the muscle may solve everything. Additionally if you have teardrop shaped implants that are rotating and/or flipping, then changing them to Stanton Anatomic buttock implants which avoid these problems may also serve you very well and improve shape and perkiness. Glad to help. 

hi
based on your pictures, it does appear the implants have flipped.....this may mean the implant was placed above the muscle rather than between the muscle.  to correct this you do need a revision butt implant surgery.  once that is done, you can at the same time or at a later time do fat grafting to the lateral and superior aspects.  please see your surgeon or a board certified plastic surgeon who does gluteal augmentations.  hope this helps.