Dang, wish I still had my account with Getty Images.
Side note, I would advise not posting any Getty images (such as uploading them a picture hosting site) other than linking to their site. Getty is one of the most notorious copyright trolls and will DMCA in a heartbeat if they see it. My older sister is an attorney and did an internship with them when she finished law school. Her only job was filing DMCA notices. Many large forums expressly prohibit Getty Images from being posted, even if they're hosted on a site that has permission to use them such as a newspaper.
Wait, was me posting links to images on the forum OK or are you just warning people about posting images on Getty Images? Sorry if I misunderstood.
You're fine since all you did was link to their website, which is what they like. What gets Getty after people would be me downloading a picture, putting it in my Photobucket account, and then me posting it on the forum, especially embedding it so the images loads in the thread.