First you need to accept Getty Images as a partner. From your profile page, click on the Manage Pictures button. At the bottom of the page you'll see information about all the partners. Follow the Partner Management link, click on the check boxes and then click on the Accept Getty Images button. Once you've done that, your images will automatically get sent to Getty for approval if you have the second check box marked. Or you can select images individually (or all the images on a page) and add them using the Edit Pictures button and the Partner Management option.
I haven't added Getty and won't. I've put a lot of time into removing content from iStock and StockXpert. This new deal is worse, with commissions taken out by both Getty and Zoonar. If iStock's royalty is insultingly low, which it is, why would anyone consider an even lower rate via Zoonar?