Boatpix takes very good large format and (in our case) gorgeous pictures of your boat under sail.
When we bought our pictures, the deal was that we had to agree to pay for the package (I think around $500 - probably a lot more now) and you could send it back if you didn't want them. There was one 11x17 and the rest were 8.5x11. There were 7 different shots. It seemed like an outrageous sum until we thought about the cost of hiring a helicopter to pictures of our boat. At the time we hemmed and hawed because it was a lot of money for us. We didn't even ask to see the pictures until we knew we would buy them if we liked them. Many years later, we are glad we did it.
At the time they were good to deal with. There was a flaw in the printing of one of the photos. They replaced it quickly. A couple of years ago, the builder of our boat asked for and received permission to use one of the shots on his website. You can see it here:
recycLed rhodes boat buying of the third kind used, recycled, new
I'd definitely check out what people are saying about them in other places but if you want aerial photos of your boat under sail you may be in luck.