From Find A Grave Frequently Asked Questions....
I found a photo of a relative on Find A Grave, can I use it?
"Photos posted to memorials on Find A Grave are copyrighted by the member who submitted the photos. Lifting the photo to use elsewhere would be a violation of copyright. You must obtain written permission from the member to use any photo for your own use. In general if you did not take the photo yourself, you do not hold the copyright to the photo."

From Find A Grave Frequently Asked Questions....
I found a photo of a relative on Find A Grave, can I use it?
"Photos posted to memorials on Find A Grave are copyrighted by the member who submitted the photos. Lifting the photo to use elsewhere would be a violation of copyright. You must obtain written permission from the member to use any photo for your own use. In general if you did not take the photo yourself, you do not hold the copyright to the photo."