You may use this websites classified section (vendor/sellers barn), many people look here. Whitetail Exchange is also an option, but you really need good pedigree's to grab bidders attention on there, a lot of bidders there are looking for good breeding stock, not saying your deer are not good, but if they don't have known pedigree's it will be tough to bring in a lot of bids.
In my opinion, the absolute best way to go about selling is to find a hunting preserve (or several) that shoots a lot of deer and that is paying decent prices for your bucks, and sell there yearly. If you are growing bucks like the one in your picture, and bigger, you will be able to sell to a preserve easily, it's just a matter of finding one that will pay you decent money. Get prices from several preserves before you sell, you can find a list of hunting preserves on PADFA.com