On April 7 iStockphoto.com will be celebrating its 10th anniversary with cash and prize giveaways for its online members. “It’s great for us to give back to our community, they’ve helped us out a lot,” says chief operating officer Kelly Thompson.

On April 7 members of the site can enter a draw to win $10,000 via email or by purchasing photo credits, the winner will be announced the next day. The online photo seller will also be will be giving away 24 hourly prizes – including Apple’s new iPad – on Twitter to followers who re-tweet for iStockphoto.

It is also launching a micro site on April 7 featuring the “faces of iStock,” which will display users’ images and comments about their experience on the site. Users can submit their images and comments at iStock10.com, and one will be selected on April 7 to win $1000.

Thompson is expecting thousands of images and comments to come from the site’s over 6 million registered users, including 80,000 photographers and contributors. “There are lots of good stories behind all of them,” he says. The submissions will “help us look back on all the things that have happened in the past 10 years.”

Kelly says he is still amazed at how quickly the company has grown in the past decade, “From a tiny little company that was selling images for 25 cents each,” he says. “We had revenues of over $200 million last year.” Kelly says he expects have their 100 millionth image download this April. Alexa Internet’s web rankings currently place iStockphoto as 233rd most visited website in the world.

He says the website has some changes ahead. “There’s some really good stuff coming out later this year that we’re working on,” he says. “I don’t want to say too much or I’ll get… killed.” Contact: iStockphoto.com, iStock10.com