Cemetery Census is a volunteer website with the goal of surveying cemeteries in North Carolina and Virginia. Some of the listings contain photographs of grave markers. Access to the listings and photos is free. The site also requests you consider sharing your cemetery surveys for listing. Listings are available by cemetery location and there is an alphabetical index of all burials.
The link for Mecklenburg County is http://cemeterycensus.com/nc/meck/index.htm