You should ask your surgeon about this as they may have different guidelines. I generally advise wearing a compression garment however not all surgeons do. The garment should be snug but not so tight that you have trouble breathing.
Each surgeon has his or her own guidelines for post operative care. Consult with your surgeon as he or she understands the scope of the surgery and the specifics about you.
Congratulations on having undergone the gynecomastia surgery. In my practice, the garment you are wearing in the photograph would suffice nicely. However, out of respect for your plastic surgeon who knows your situation best (and is ultimately responsible for your care) best to run your questions/pictures by him/her. Best wishes.
I just want to know where you found this garment, because I think it looks fantastic! I usually send my gynecomastia patients home in a compression vest and have them wear it for 2-3 weeks. Every once in a while I get someone like you that the vest does not fit well, and after a week it starts to hurt. I usually put those patients in an underarmour shirt and tell them, "the compression should feel good, too tight or too loose and it hurts." All that being said, while I think this compression looks fantastic, I did not do your surgery and therefore don't know if there was some reason your surgeon wanted something different. I would contact the and send this picture just to be safe. Your early result looks great!