Is my donor area sufficient? (Photos)

Photos cannot determine if you would be a good candidate for surgery.  You need an examination and the doctor needs to understand your goals and expectations.

From what I can see in the pictures, it appears you have a sufficient donor area. There are many factors that go into a successful hair transplant - donor density being just one of them. If in fact your scalp donor density is not sufficient enough to get your hair to where you want it to be, there are other innovative options available such as body hair transplantation, which involves extracting follicles from the beard, chest, or other viable areas. As far as the number of grafts needed, we'd need better pictures to accurately answer this. Number of grafts needed versus number of grafts that can be extracted often differ. Most FUE transplants are capable of yielding anywhere from 500-3,500 grafts. These numbers will vary a great deal based on the patient, the hair, and the goal result. With the areas you're wanting to fill in and the results you're looking to get, you will likely need on the high end of this number. The reason we stop around 2500 grafts with FUE is to avoid risks associated with mega-sessions. Many surgeons (especially those abroad and/or inexperienced) will tell you 'the more the better.' This is not always true and can cause irreversible damage such as shock hair loss, increased scarring, and a 'worse-off than before' look. Make sure that you thoroughly research your prospective hair transplant surgeon. Not all are created equal. 

Thanks for submitting your photos. Based on them your donor side does not look very strong but in between 3000-3500 grafts with FUE method surgery can be transplanted and it will cover around 70 % of your balding area. A second surgery will be needed after a year if your donor is suitable.