I had a hair transplant and was charged for 1900 grafts. Do you think I've been given the right quantity? (Photo)

If you don't trust your doctor who just did your surgery, how would you trust doctors you don't even know on the Internet?  It is best to voice your concern to your doctor.  It seems they were honest enough to give you a refund.  If this is not enough you can ask your doctor to see your surgical records which should show the accounting of the grafts.

It is not easy to tell by photos. If you went to a reputable dedicated hair clinic you should be ok. Always keep up with your follow ups. 

From the pictures, this is what I would expect 1900 grafts to look like but if you doubt your doctor's honesty, ask him for the count sheets which will be part of the surgical record at the time you had it done. The doctor must give it to you as it is part of your medical record.